Volumen VI No.2 julio 2007

ACANTHAMOEBA KERATITIS. A REVIEW Penny McAllum, MBChB, Allan Slomovic, MD, FRCS(C). ECTASIA POST CIRUGÍA REFRACTIVA Eduardo Arenas Archila MD. Christine Kornerup Fals MD. FACTORES DE CRESCIMENTO NA RETINOPATÍA DA PREMATURIDADE GROWTH FACTORS AND RETINOPATHY OF PREMATURITY Sofi a AlmadaMD, Duarte Amado MD, João Paulo Cunha MD, Margarida Marques MD. A LONG-TERM COMPLICATION OF RETINAL REATTACHMENT SURGERY: EXTRUSION OF THE EXOPLANT Chun Cheng Lin Yang1, M.D., M.Sc. Preserva la visión alcanzando las menores presiones-objetivo en más pacientes

Investigadores de diversos estudios, (AGIS, Shirakashi, Shields) han comprobado que alcanzar y mantener la PIO entre 14 y 15 mmHg reduce la progresión de pérdida del campo visual1,2,3.

Lumigan® alcanza la PIO-objetivo de 14/15 mmHg en un mayor número de pacientes:

® ® dorzolamida/ ® vs. timolol 4 vs. vs. latanoprost 6 timolol 5

Porcentaje de Pacientes que alcanzaron la PIO-Objetivo ≤14 21% 9% 17% 2% 19% 9%

Porcentaje de Pacientes que alcanzaron la PIO-Objetivo ≤15 31% 16% 24% 9% 29% 14%

Lumigan® (bimatoprost) Forma farmacéutica y presentación.esentación.Frascos cuenta-gotas conteniendo 5 ml de solución oftalmológica estéril de bimatoprost a 0,03%. USO ADULTO.Composición. Cada ml contiene: 0,3 mg de bimatoprost. Vehículo: cloreto de sódio, fosfato de sódio hepta-hidratado, ácido cítrico mono-hidratado, ácido clorídrico y/o hidróxido de sódio, cloruro de benzalconio y agua purificada qsp. Indicaciones. LUMIGAN® (bimatoprost) es indicado para la reducción de la presión intra-ocular elevada en pacientes con glaucona o hipertensión ocular.Contraindicaciones. LUMIGAN® (bimatoprost) está contraindicado en pacientes con hipersensibilidad al bimatoprost o cualquier otro componente de la fórmula del producto. Precauciones y Advertencias. Advertencias. Fueron relatados aumento gradual del crescimiento de las pestañas en el largo y espesura, y oscurecimiento de las pestañas (en 22% de los pacientes después 3 meses, y 36% después 6 meses de tratamiento), y, oscurecimiento de los párpados (en 1 a <3% de los pacientes después 3 meses y 3 a 10% de los pacientes después 6 meses de tratamiento). También fue relatado oscurecimiento del íris en 0,2% de los pacientes tratados durante 3 meses y en 1,1% de los pacientes tratados durante 6 meses. Algunas de esas alteraciones pueden ser permanentes. Pacientes que deben recibir el tratamiento de apenas uno de los ojos, deben ser informados a respecto de esas reacciones. Precauciones LUMIGAN® (bimatoprost) no fue estudiado en pacientes con insuficiencia renal o hepática y por lo tanto debe ser utilizado con cautela en tales pacientes.Las lentes de contacto deben ser retiradas antes de la instilación de LUMIGAN® (bimatoprost) y pueden ser recolocadas 15 minutos después. Los pacientes deben ser advertidos de que el producto contiene cloruro de benzalconio, que es absorvido por las lentes hidrofílicas.Si más que un medicamento de uso tópico ocular estuviera siendo utilizado, se debe respetar un intervalo de por lo menos 5 minutos entre las aplicaciones.No está previsto que LUMIGAN® (bimatoprost) presente influencia sobre la capacidad del paciente conducir vehículos u operar máquinas, sin embargo, así como para cualquier colírio, puede ocurrir visión borrosa transitoria después de la instilación; en estos casos el paciente debe aguardar que la visión se normalice antes de conducir u operar máquinas. Interacciones medicamentosas.medicamentosas.Considerando que las concentraciones circulantes sistemicas de bimatoprost son extremadamente bajas después múltiplas instilaciones oculares (menos de 0,2 ng/ml), y, que hay varias vías encimáticas envueltas en la biotransformación de bimatoprost, no son previstas interacciones medicamentosas en humanos. No son conocidas incompatibilidades. Reacciones adversas. LUMIGAN® (bimatoprost) es bien tolerado, pudiendo causar eventos adversos oculares leves a moderados y no graves.Eventos adversos ocurriendo en 10-40% de los pacientes que recibieron doses únicas diarias, durante 3 meses, en orden decreciente de incidencia fueron: hiperenia conjuntival, crecimento de las pestañas y prurito ocular.Eventos adversos ocurriendo en aproximadamente 3 a < 10% de los pacientes, en orden decreciente de incidencia, incluyeron: sequedad ocular, ardor ocular, sensación de cuerpo estraño en el ojo, dolor ocular y distúrbios de la visión.Eventos adversos ocurriendo en 1 a <3% de los pacientes fueron: cefalea, eritema de los párpados, pigmentación de la piel periocular, irritación ocular, secreción ocular, astenopia, conjuntivitis alérgica, lagrimeo, y fotofobia.En menos de 1% de los pacientes fueron relatadas: inflamación intra-ocular, mencionada como iritis y pigmentación del íris, ceratitis puntiforme superficial, alteración de las pruebas de función hepática e infecciones (principalmente resfriados e infecciones de las vías respiratorias).Con tratamientos de 6 meses de duración fueron observados, además de los eventos adversos relatados más arriba, en aproximadamente 1 a <3% de los pacientes, edema conjuntival, blefaritis y astenia. En tratamientos de asociación con betabloqueador, durante 6 meses, además de los eventos de más arriba, fueron observados en aproximadamente 1 a <3% de los pacientes, erosión de la córnea, y empeoramiento de la acuidad visual. En menos de 1% de los pacientes, blefarospasmo, depresión, retracción de los párpados, hemorragia retiniana y vértigo.La frecuencia y gravedad de los eventos adversos fueron relacionados a la dosis, y, en general, ocurrieron cuando la dosis recomendada no fue seguida.Posología y Administración.Administración.Aplicar una gota en el ojo afectado, una vez al día, a la noche. La dosis no debe exceder a una dosis única diaria, pues fue demostrado que la administración más frecuente puede disminuir el efecto hipotensor sobre la hipertensión ocular.LUMIGAN® (bimatoprost) puede ser administrado concomitantemente con otros productos oftálmicos tópicos para reducir la hipertensión intra-ocular, respetándose el intervalo de por lo menos 5 minutos entre la administración de los medicamentos. VENTA BAJO PRESCRIPCIÓN MÉDICA.“ESTE PRODUCTO ES UM MEDICAMENTO NUEVO AUNQUE LAS INVESTIGACIONES HAYAN INDICADO EFICACIA Y SEGURIDAD, CUANDO CORRECTAMENTE INDICADO, PUEDEN SURGIR REACCIONES ADVERSAS NO PREVISTAS, AÚN NO DESCRIPTAS O CONOCIDAS, EN CASO DE SOSPECHA DE REACCIÓN ADVERSA, EL MÉDICO RESPONSABLE DEBE SER NOTIFICADO.

1. The AGIS Investigators: The Advanced Glaucoma Intervetion Study - The Relationship Between Control of Intraocular Pressure and Visual Field Deterioration. Am. J. Ophthalmol, 130 (4): 429-40, 2000. 2. Shirakashi, M. et al: Intraocular Pressure-Dependent Progression of Visual Field Loss in Advanced Primary Open-Angle Glaucoma: A 15-Year Follow-Up. Ophthalmologica, 207: 1-5, 1993. 3. Mao, LK; Stewart, WC; Shields, MB: Correlation Between Intraocular Pressure Control and Progressive Glaucomatous Damage in Primary Open-Angle Glaucoma. Am. J. Ophthalmol, 111: 51-55, 1991. 4. Higginbotham, EJ et al. One-Year Comparison of Bimatoprost with Timolol in Patients with Glaucoma or Ocular Hypertension. Presented at American Academy Ophthalmology, Nov 11-14, 2001. 5. Gandolfi, S et al. Three-Month Comparison of Bimatoprost and Latanoprost in Patients with Glaucoma and Ocular Hypertension. Adv. Ther, 18 (3): 110-121, 2001. 6. Coleman, AL et al: A 3-Month Comparison of Bimatoprost with Timolol/Dorzolamide in Patients with Glaucoma or Ocular Hypertension. Presented at American Acedemy of Ophthalmol, New Orleans, La, 2001.

Mejor comodidad posológica: 1 vez al día. No requiere refrigeración. Presentación conteniendo 3 ml. julio 2007

Mark J. Mannis, MD University of California, Davis Sacramento, California Editor-in-Chief

Cristian Luco, MD Teresa J. Bradshaw Santiago, Chile Arlington, Texas Associate Editor Managing Editor

EDITORIAL BOARD

Eduardo Alfonso, MD David E. Pelayes, MD Miami, Florida U.S.A. Buenos Aires, Argentina

Eduardo Arenas, MD Alfredo Sadun, MD Bogotá, Colombia Los Angeles, California U.S.A.

J. Fernando Arévalo, MD José Benítez del Castillo Sanchez, MD Caracas, Venezuela Madrid, Spain

José A. Roca Fernandes, MD Allan Slomovic, MD Lima, Perú Toronto, Ontario, Canada

Denise de Freitas, MD Luciene Barbosa de Sousa, MD São Paulo, Brazil São Paulo, Brazil

Marian Macsai, MD Lihteh Wu, MD Chicago, Illinois U.S.A. San José, Costa Rica

OFFICERS Enrique Graue Wiechers, MD Mexico City, Mexico President, Pan-American Association of Ophthalmology

Rubens Belfort, MD São Paulo, Brazil Chairman of the Board, Pan-American Ophthalmological Foundation

PRODUCTION STAFF Juan Pablo Cuervo Graphic Design

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PAOF INDUSTRY SPONSORS Advanced Medical Optics Inc. Carl Zeiss Meditec Inc. Alcon Inc. Merck & Co. Inc. Allergan Inc. Novartis Inc. Bausch & Lomb Inc. Santen Inc.

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PAN-AMERICA : 3 MENSAJE DEL PRESIDENTE MESSAGE FROM THE PRESIDENT

ENRIQUE GRAUE Presidente, Asociación Panamericana de Oftalmología Outgoing President, Pan-American Association of Ophthalmology

Después de dos años un balance se impone. After two years, balance is a must.

L a regionalización del mundo, en un mundo que tiende a ser global, I n a world that tends to be global, division has its own strengths and presenta fortalezas y debilidades. Como agrupación continental nuestra weaknesses. As a continental association, our greatest virtue is the union gran fortaleza es la unión que como continente tenemos. Y en que sólo we share as a continent. There are three major languages, two of which existen tres lenguas, dos de ellas, el Portugués y el Español son muy –Portuguese and Spanish- have many similarities. We share race, religion similares entre sí, compartimos con Brasil, no sólo las raíces lingüísticas and, culture. sino también, raza, cultura y religión. The other language, English, is fortunately, a universal language. La otra lengua, la inglesa, es para nuestra fortuna una lengua universal. Our communication is fluid and respectful. Our interest in improving La comunicación entre nosotros es fluida y respetuosa. Esa es nuestra ophthalmology also unites us as a continent. gran fortaleza. Nos une también, como continente, nuestro interés por la Our weaknesses reside in the existing economic disparities between superación de la oftalmología. nations, and in some occasions, in an accentuated nationalism that hampers Nuestras debilidades, son las diferencias económicas entre naciones, our efforts to breach frontiers and strengthen bonds. Each country has its y a veces, un nacionalismo acentuado que nos impide romper fronteras own health politics and sovereign ideals. The Association recognizes and y fortalecer lazos. Cada país tiene sus políticas de salud y soberanía. respects these differences, and by so doing, sometimes faces situations La Asociación es respetuosa de estas diferencias y al serlo, se enfrenta with difficult solutions. Nevertheless, we advance continuously. en ocasiones a situaciones de difícil solución. Sin embargo, en ellas During this period, the programs and objectives of the committees on seguimos avanzando. the Prevention of Blindness, eye banking, and education were strengthened Durante esta gestión se fortalecieron y ampliaron los programas y and broadened. The bond with The American Academy of Ophthalmology objetivos de los comités de prevención de ceguera, de bancos de ojos, was strengthened, and we all received the Academy Express, for which y de educación. Se estrecharon los lazos con la Academia Americana work has begun on both Spanish and Portuguese editions. There is also the de Oftalmología y recibimos ya, todos, las comunicaciones Express de possibility for translation of the Academy’s preferred practice patterns. la misma, se trabaja ya en la edición de ella en español y portugués y Ties with the International Council of Ophthalmology also grew stron- la posible traducción de los manuales de la Academia de las guías de ger. The result of this union was the development of training courses for prácticas preferenciales. professors of ophthalmology that are now held in Mexico, Peru, and, in a Se fortalecieron los lazos de unión con el Internacional Council of matter of months, in Argentina. The committee on professional relations Ophthalmology y fruto de esta unión son los cursos de preparación a expanded and strengthened. As a result, so did leadership courses di- los profesores de oftalmología efectuados en México, Perú y en unos rected at young members of the association, in whose hands the future of meses más, en Argentina. Se fortaleció y amplió el comité de relaciones the organization rests. profesionales y a través de él los cursos de liderazgo dirigidos a los Vision Pan America grew in size and was edited and distributed at miembros jóvenes de nuestras sociedades y entre quienes descansará el every opportunity. The journal received several grants making its distri- futuro de esta Asociación. bution more reasonable. Vision pan America, se amplío en tamaño y se editó y distribuyó Overall, I believe we can say that we have grown and become both con toda oportunidad. Se otorgaron becas y se hizo más justa y equitativa stronger and more unified. I hand the association over the Dr. Richard la distribución de ellas. Abbot, who was elected to serve as president two years ago. Dr. Abbott, in En un balance general creo que podemos decir que crecimos y nos addition to having great professional prestige, is a sensible human being, hicimos más fuertes y unidos. Entrego la Asociación al Dr. Richard Abbot, with a remarkable work ethic, and tremendous organizational skills. The quien fuera electo para ocuparla hace ya dos años. El Dr. Abbot, además association could not be in better hands. de su gran prestigio profesional es un ser humano sensible, de una gran I extend my sincerest thanks to all of the members of the Pan-American capacidad de trabajo y de una insuperable organización. En mejores ma- Association of Ophthalmology, to its delegates, and, in particular, to those nos no podría quedar la Asociación. who served actively and unselfishly on the executive committee. Mi más profundo agradecimiento a todos los miembros de la Asociación Panamericana de Oftalmología, a sus delegados y en forma muy particular a quienes participaron desinteresada y activamente en el Comité Ejecutivo de la Asociación.

Esta en mi última editorial como Presidente de la Asociación Panamericana de This is my last editorial as President of the Pan-American Association of Ophthalmology. Oftalmología. Presidir esta Asociación ha sido un gran honor y una experiencia Presiding has been a great honor and an unforgettable and fulfilling experience. enriquecedora e inolvidable.

4 : PAN-AMERICA REVIEW julio 2007 Acanthamoeba Keratitis A Review

Penny McAllum, MBChB1,2 Allan Slomovic, MD, FRCS(C)1,2 Author for reprints: 1. Department of Ophthalmology, Toronto Western Hospital, Toronto, Ontario, Canada. Dr. Allan Slomovic 2. Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Toronto Western Hospital 6E. Ontario, Canada. 399 Bathurst St Toronto Ontario M5T 2S8 Canada

None of the authors have any fi nancial or proprietary interest in any of the products or methods mentioned in this paper.

Abstract for contact lens disinfection and storage.9 Unlike systemic Acanthamoeba infections, Acanthamoeba keratitis is a sight-threat- Estimates of the incidence of Acanthamoeba which typically occur in immunocompromised ening corneal infection, which is rare, but may keratitis in the United Kingdom, Europe and individuals, Acanthamoeba keratitis usually be increasing in frequency. The spectrum of Hong Kong are about 0.33 per 10,000 soft occurs in healthy young people.15 disease ranges from mild, with an excellent contact lens wearers per year.10 There are no The most important risk factor for Acan- prognosis, to severe and complicated with recent estimates for incidence of the infection thamoeba keratitis is contact lens wear, which significant morbidity. Its diagnosis is frequently in America, however localised epidemics is associated with at least 80% of cases in delayed and the index of suspicion needs to be have been described,11 and in the last year developed countries1,12,16,17,18 All types of con- high, particularly in cases of atypical keratitis there have been reports of dramatic increases tact lenses have been implicated, although in in contact lens wearers. Prolonged medical in the number of cases of Acanthamoeba most recent reports disposable soft contact therapy with multiple anti-amoebal agents is keratitis.12,13 We have also seen this trend at lenses predominate.12,18 The first generation usually required and penetrating keratoplasty our own institution. of the increasingly popular silicone hydrogel is sometimes necessary for visual rehabilitatio. contact lenses and one of the newer second Pathogenesis and Risk Factors generation silicone hydrogels (O2 OPTIX, Introduction Ciba Vision, Duluth, Georgia, USA), have a Acanthamoeba keratitis (AK) is a rare, Acanthamoebae are ubiquitous free-living higher affinity for Acanthamoeba compared sight threatening corneal infection, which protozoans, found com-monly in fresh, salt or with or conventional soft lenses, which may occurs predominantly in contact lens wearers chlorinated water, soil and other environments. increase the risk of keratitis caused by this in developed countries,1 and in cases of At least 8 species of Acanthamoeba have organism.19,20 The other second generation 6 ocular trauma in developing countries.2,3,4 been recognized as causes of keratits, silicone hydrogel (Acuvue Advance, Johnson It was first recognized in 1973,5 but the with A. castellani being the most common & Johnson Vision Care, New Jacksonville, incidence in-creased dramatically in the corneal isolate. Acanthamoeba exists as Florida, USA) has lower Acanthamoeba at- 1980’s, paralleling the popularity of contact trophozoites, which are motile organisms, tachment rates, similar to conventional hydro- lens wear.6 It is thought to have become capable of penetrating through intact corneal gels, so may be safer.21 Rigid gas permeable less common since then,7,8 related to the epithelium.14 In unfavorable conditions, such lenses, when used overnight for orthokeratol- abolition of homemade saline and chlorine- as extremes of pH, osmolarity or temperature ogy, may also pose an increased risk.3,22,23,24 based contact lens solutions, and possibly and in the presence of many antimicrobial Although a few cases of Acanthamoeba kera- the introduction of multipurpose solutions agents, trophozoites rapidly transform into titis have been described in daily disposable dormant and highly resistant cysts. soft contact lens wearers,25 these are prob-

a b c

Figure 1: Color photographs demonstrating common presenting features of Acanthamoeba keratitis. (a) punctate epithelial disease with pseudodendrite, stained with fl uorescein and illuminated with cobalt blue light, (b) ring stromal infi ltrate with an epithelial defect and a hypopyon (c) radial keratoneuritis involving stromal nerves with early stromal infi ltrate.

PAN-AMERICA : 5 REVIEW ably the safest type of contact lenses, as they obviate the need for contact lens solution and cases.26 Poor contact lens hygeine is a very frequent finding in cases of Acanthamoeba keratitis.25,27,28 Other common risk factors include cor- neal trauma, particularly involving organic material2,3,4,5 and exposure to contaminated water,11,16,17,29 including tap water, contact lens solutions, swimming pools and hot tubs. Many patients with Acanthamoeba keratitis a b have more than one identifiable risk factor.6 Clinical Features Wide variability in the clinical presenta- tion of Acanthamoeba keratitis may relate to variability in virulence among strains of Acan- thamoeba and differences in host immune responses.30 Clinical features may follow a protracted waxing and waning course.28,30 Symptoms of Acanthamoeba keratitis are non-specific and include foreign-body sen- c d sation, photophobia, pain, watery discharge Figure 2: and blurring of vision. Ocular pain which is (a) Haematoxylin and eosin stained corneal stromal biopsy demonstrating Acanthamoeba cyst, (b) electron disproportionate to clinical findings is recog- microscopic image of double-walled Acanthamoeba cyst, (c) confocal microscopic image of corneal stroma demonstrating numerous Acanthamoeba cysts, (d) confocal microscopic image demonstrating Acanthamoeba cysts nized as a hallmark of Acanthamoeba kerati- adjacent to stromal nerves. (Confocal images courtesy of Marc Lafontaine, University of Ottawa Eye Institiute.). tis, however this complaint is neither pathog- nomonic nor omnipresent.28,30 Examination findings are of a, generally infectious keratitis, such as Herpes simplex, covery of Acanthamoeba can be delayed.38 unilateral, keratitis associated with perilim- bacterial or fungal keratitis and there may be Cultures from contact lenses, solutions and bal conjunctival injection and chemosis. In an initial apparent response to treatment with cases may give supportive evidence, but the early stages of infection corneal changes antiviral, antibacterial, antifungal or cortico- should not be relied upon for diagnostic include superficial epithelial lesions, such as steroid therapy, which can cloud the picture confirmation. When cultures and stains are punctate erosions, sometimes with a ‘snow- further. In many cases, it is not until the dis- non-confirmatory, which is particularly prob- lematic in more advanced disease involving storm’ appearance, microcystic edema or ease has progressed significantly and other the deep stroma, a corneal biopsy may be dendritiform lesions.1,31 Perineural infiltrates, treatments have failed, that the diagnosis of required.28 Histopatholological examination also known as radial keratoneuritis, also oc- Acanthamoeba keratitis is considered. The of the specimen rarely demonstrates tro- 1,32 cur in more than half of early cases and first step in making the correct diagnosis is phozoites, but double-walled round or oval 31 are diagnostic of Acanthamoebal infection. having a high index of suspicion, particularly cysts are characteristic. Careful preparation, More advanced disease is often character- in contact lens wearers and in atypical kera- experienced laboratory personnel and strict ized by ring stromal infiltrates with overly- titis with severe pain and dendritiform or ring diagnostic criteria are essential for accurate ing epithelial defects, progressing to frank ulcers. daignosis.39 ulceration, intrastromal abscess, corneal Confirmation of the diagnosis should Tandem scanning confocal microscopy neovascularization, stromal thinning and, always be attempted, as clinical features are has gained popularity in recent years as a 1,3,33,34 uncommonly, perforation. Keratitis is rarely diagnostic and prolonged and some- non-invasive diagnostic test for Acantham- commonly associated with anterior uveitis, times toxic treatments should be justified. oeba keratitis.40,41 In a cooperative patient, which may be mild, or severe with hypopyon Corneal epithelial scrapings are examined both trophozoites and particularly cysts can and endothelial plaque formation.1,3,17 Com- directly with one or more special stains, in- be rapidly identified at varying stromal lev- plications of severe uveitis include cataract els, as well as thickened stromal nerves. It is and glaucoma.1,17,35 Occasionally scleritis cluding Giemsa, calcofluor white, periodic acid-Schiff, haematoxylin and eosin, Gram, particularly useful when conventional micro- may develop, usually contiguous with cor- biology in inconclusive, for differentiating 1,35,36 Wright’s and acridine orange. Corneal scrap- neal infiltration. Acanthamoeba from fungal keratitis41 and for ings are best cultured on Escherichia coli- distinguishing between medication toxic- Diagnosis seeded non-nutrient agar, where trophozoites ity and active infection.30 In a recent report Diagnosis of Acanthamoeba keratitis can leave characteristic trails, although Acan- the Heidelberg retina tomograph II (HRTII) be difficult and is often delayed, which may thamoeba may also grow on Sabouraud’s, with the cornea module was also found to lead to a severe course and poor visual out- blood or chocolate agar.37 Cultures should be useful in the diagnosis of Acanthamoeba 1,18,28,30 come. It often mimics other types of be maintained for at least 2 weeks, as re- keratitis.42

6 : PAN-AMERICA julio 2007

Other specialized techniques for labo- Other topical agents that have been sug- Surgical management may be required in ratory identification of Acanthamoeba from gested in the treatment of Acanthamoeba ker- a minority of eyes with Acanthamoeba kerati- corneal scrapings, including polymerase atitis include the imidazoles as 1% solutions, tis. Penetrating keratoplasty performed when chain reaction (PCR),43 scanning electron however these are ineffective against cysts keratitis remains active has a very guarded microscopy and indirect immunofluorescent and should only be considered if chlorhexi- prognosis.51 Recurrence of Acanthamoeba staining,44 have also been reported. These dine or PHMB cannot be obtained.31 The use in-fection in the graft can occur within days.1 may have increased sensitivity and specific- of oral imidazoles, such as ketoconazole and If keratoplasty is unavoidable because of ity compared with conventional microbiol- itraconazole in Acanthamoeba keratitis is not a large corneal perforation, intensive anti- ogy, but are not widely available outside of recommended, as the drug levels achieved in amoebal treatment should be continued research laboratories. the cornea are insufficient to be even tropho- post-opera-tively, as well as topical steroids zoiticidal, let alone cysticidal.31 and the patient should be advised that repeat Management There are several possible future topical surgery may be required at a later date. Other The management of Acanthamoeba kera- anti-amoebals, which are currently under in- options reported for surgical management of titis is often challenging. Epithelial debride- vestigation and show some promise. These recalcitrant keratitis with persistent epithelial ment for microscopy and culture also has a include some cancer chemotherapy agents, defect include deep lamellar keratectomy useful therapeutic effect in early epithelial such as MGMB and CHS828, some antima- with a conjunctival flap52 and amniotic mem- disease, by decreasing the amoebal load and larials, such as proguanil (Malarone, Glaxo- brane transplantation.53 Whenever possible aiding medication penetration. SmithKline, Middlesex, UK) and chlorguanil the eye should be managed medically and There remains no consensus on medi- (Lapudrine, GlaxoSmithKline, Middlesex, UK) the inflammation allowed to settle. If sig- cal management and various therapeutic and a new nonguanidino group compound nificant corneal scarring then limits vision, regimens have been suggested. As the cyst known as alkylphosphocholine-1 (APC-1, penetrating keratoplasty may be considered form of Acanthamoeba can be highly resis- Miltefosine, Zentaris, Frankfurt, Germany).31 after the eye has remained quiet for at least 3 tant to treatment, combination therapy with Initial therapy for Acanthamoeba kerati- months following cessation of anti-amoebal 2 anti-amoebal agents is generally recom- tis should consist of hourly, round the clock, treatment. In this situation graft survival of mended.31,45 However, monotherapy with one chlorhexidine or PHMB 0.02%, usually to- <90% at 2 years has been reported.1,54 cysticidal agent, and if necessary increasing gether with hourly propamidine or hexamidine the concentration to 2 or 3 times the stan- 0.1%. After 2-3 days the overnight treatment Conclusion dard strength, has been recently reported to may be discontinued and daytime treatment Acanthamoeba keratitis remains a chal- be highly effective.46 is slowly tapered to four times a day. The du- lenging condition to diagnose and treat ef- The mainstay of therapy for Acantham- ration of anti-amoebal therapy varies greatly, fectively. Despite improvements in contact oeba keratitis is the cationic antiseptics depending on disease severity and treatment lenses and solutions, its incidence may be chlorhexidine and polyhexamethyl biguanide response. In very early epithelial disease 2 on the rise again in contact lens wearers. Eye (PHMB).45,47 These agents, commonly used weeks may be sufficient, but more commonly care professionals need to educate contact as pool cleaners, are generally highly active prolonged treatment for 2-6 months is nec- lens wearers regarding correct lens care and against both trophozoites and cysts and are essary,31 and some severe cases may require maintain a high index of suspicion for Acan- usually used in concentrations of 0.02%. 12 months or more.6 thamoebal infection in cases of keratitis, par- Neither is commercially available, so the After discontinuation of therapy, patients ticularly atypical or dendritiform keratitis in expertise of a compounding pharmacy is must remain under close supervision for sev- contact lens wearers. Appropriate stains and necessary. One of these agents is usually eral months, as some cysts may have sur- cultures of corneal scrapings should always combined with a topical diamidine, such as vived treatment and could result in a recur- be taken and corneal biopsy may be neces- propamidine isethionate 0.1% (Brolene, rence of active keratitis.28 sary when repeated cultures of corneal scrap- Aventis, Kent, UK), or hexamidine isethion- Adjunctive agents for management of ings are negative. Confocal microscopy can ate 0.1% (Desmodine, Vivier Pharma Inc, pain and inflammation in Acanthamoeba ke- also be a valuable diagnostic tool. The man- Quebec, Canada), which are effective against ratitis include topical cycloplegics and oral agement of Acanthamoeba keratitis should in- trophozoites, and have some cysticidal activ- nonsteroidal anti-inflammatories, which are clude intensive PHMB and/or chlorhexidine, ity.10,48 They may be moderately toxic to the often helpful. Narcotic analgesics may also and should be combined with a diamidine. cornea with intensive use. The diamidines be required for pain management.26 Prolonged treatment is often required. New are not readily available in North America, The use of topical corticosteroids in anti-amoebal agents may become available in but can be obtained over the counter in many Acanthamoeba keratitis is controversial. In the next few years; however the cationic anti- countries. general steroids should be avoided, or at septics are likely to remain the first line agents The topical aminoglycoside neomycin least delayed, as they may lead to prolonga- in the foreseeable future. After cessation of was used in combination with propamidine tion of medical treatment.49 However, they anti-amoebal treatment patients must remain in the 1980’s, prior to the introduction of the may be used with caution in the presence under regular review for detection of any re- cationic antiseptics. However, it is not cys- of very severe pain or anterior uveitis, scle- current keratitis, and if penetrating keratoplasty ticidal, may lead to resistance and mutant ritis or late inflammatory reactions,31,49 while is required it should be delayed for at least 3 amoebae, and is frequently associated with the patient is on anti-amoebal therapy. Oral months to ensure the infection is cured. hypersensitivity reactions, so it is no longer immunosuppression with corticosteroids recommended for the treatment of Acantham- or other agents may be necessary in severe oeba keratitis.10,31 sclerokeratitis.50

PAN-AMERICA : 7 REVIEW

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Outbreak of keratitis presumed - A six year epidemiological review from a tertiary care eye hospital in South to be caused by Acanthamoeba. Am J Ophthalmol 1996; 121:129-142 India. Indian J Med Microbiol 2004; 22:226-230 31. Seal D. Treatment of Acanthamoeba keratitis. Expert Rev Anti-Infect Ther 5. Nagington J, Watson PG, Playfair TJ et al. Amoebic infection of the eye. 2003; 1:205-208 Lancet 1974; 2:1537-1540 32. Moore MB, McCulley JP, Kaufman HE, et al. Radial keratoneuritis as a 6. Schaumberg DA, Snow KK, Dana MR. The epidemic of Acanthamoeba presenting sign of Acanthamoeba keratitis. Ophthalmology 1986; 93:1310-1315 keratitis: where do we stand? Cornea 1998; 17:3-10 33. Theodore FH, Jakobeic FA, Juechter KB, et al. The diagnostic value of a 7. Seal DV, Beattie TK, Tomlinson A, et al. Acanthamoeba keratitis. Br J ring infi ltrate in Acanthamoeba keratitis. Ophthalmology 1985; 92:1471-1479 Ophthalmol 2003; 87:516-7 34. Cohen EJ, Buchanan HW, Laughrea PA, et al. Diagnosis and management 8. Lam D, Houang E, Lyon D, et al. Incidence and risk factors for microbial of Acanthamoeba keratitis. Am J Ophthalmol 1985; 100:389-395 keratitis in Hong Kong: comparison with Europe and North America. Eye 2002; 35. Duguid IG, Dart JK, Morlet N, et al. Outcome of Acanthamoeba keratitis 16:608-18 treated with Polyhexamethyl biguanide and propamidine. Ophthalmology 9. Stevenson RWW, Seal DV. Has the introduction of multi-purpose solutions 1997; 104:1587-1592 contributed to a reduced incidence of Acanthamoeba keratitis in contact lens 36. Mannis MJ, Tamaru R, Roth AM, et al. Acanthamoeba sclerokeratitis: wearers? Contact Lens Ant Eye 1998; 21:89-92 determining diagnostic criteria. Arch Ophthalmol 1986; 104:1313-1317 10. Seal DV. Acanthamoeba keratitis update: incidence, molecular epidemiology 37. Wiens JJ, Jackson B. Acanthamoeba keratitis: an update. Can J Ophthalmol and new drugs for treatment. Eye 2003; 17:893-905 1988; 23:107-110 11. Meier PA, Mathers WD, Sutphin JE, et al. An epidemic of presumed 38. Armstrong M. The laboratory investigation of infective keratitis. Br J Acanthamoeba keratitis that followed regional fl ooding. Results of a case-control Biomed Sci 1994; 51:65-72 investigation. Arch Ophthalmol 1998 Aug; 116:1090-1094 39. Silvany RE, Luckenbach MW, Moore MB. The rapid detection of 12. Joslin CE, Tu EY, McMahon TT, et al. Epidemiological characteristics of Acanthamoeba in paraffi n-embedded sections of corneal tissue with calcofl uor a Chicago-area Acanthamoeba keratitis outbreak. Am J Ophthalmol 2006; white. Arch Ophthalmol 1987; 105:1366-1367 142:212-217 40. Kaufman SC, Musch DC, Belin MW, et al. Confocal microscopy: a report by 13. Rocha FN, Hammersmith KM, Rapuano CJ, et al. Nine cases of the American Academy of Ophthalmology. Ophthalmology 2004; 111:396-406 Acanthamoeba in 15 months: is it back? American Academy of Ophthalmology 41. Parmar DN, Awwad ST, Petroll WM, et al. Tandem scanning confocal Annual Meeting; 16 October 2005; Chicago Illinois; San Francisco: American corneal microscopy in the diagnosis of Acanthamoeba keratitis. Ophthalmology Academy of Ophthalmology; 2005. p. 16414. 2006; 113:538-547 14. Omana-Molina M, Navarro-Garcia F, Gonzalez-Robles A, et al. Induction 42. Bourcier T, Dupas B, Borderie V, et al. Heidelberg retina tomograph II of morphological and electrophysiological changes in hamster cornea after in fi ndings of Acanthamoeba keratitis. Ocul Immunol Infl amm. 2005;13:487-492 vitro interaction with trophozoites of Acanthamoeba spp. Infect Immun. 2004; 43. Lehmann OJ, Green SM, Morlet N, et al. Polymerase chain reaction 72:3245-3251 analysis of corneal epithelial and tear samples in the diagnosis of Acanthamoeba 15. Martinez AJ, Visvesvera GS, Chandler FW. Free-living amoebic infection. keratitis. Invest Ophthalmol Vis Sci. 1998; 39:1261-1265 In: Pathology of infectious diseases, Vol. II. Conner DH, Schwartz FC, et al 44. 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8 : PAN-AMERICA julio 2007 Ectasia post cirugía refractiva

Eduardo Arenas Archila MD.1 Christine Kornerup Fals MD.2 1. Profesor especial Unidad de Oftalmología. Universidad Nacional. Departamento de Oftalmología Universidad Javeriana. Bogotá, Colombia. 2. Residente de Oftalmología. Departamento Universidad Javeriana. Bogotá, Colombia.

Historia. ratomileusis)22.que gracias a su exactitud y a La ectasia corneana puede aparecer des- su relativa facilidad de ejecución se difundió de pocos meses hasta varios años después En 1930 Sato en el Japón describió la rápidamente por el mundo y empezó a ser de practicada la cirugía44,45,46,47,48. Uno de los técnica de la Queratotomía posterior para el practicada en forma masiva, aparentemente factores de riesgo para desencadenar ectasia tratamiento del Queratocono, después de ob- sin mayores complicaciones23. Fue Seiler son las cirugías múltiples49. Se sugiere que en servar el comportamiento de ciertas córneas nuevamente quien advirtió sobre los riesgos aquellos ojos con córneas delgadas sería me- con rupturas espontáneas de la membrana de producir ectasias después de estos pro- jor practicar Cirugía fotorefractiva (PRK), por de Descemet.1 Un docena de años mas tarde cedimientos sólo hasta el año 199824,25 y a ser más superficial la ablación. Sin embargo publicó sus resultados en el tratamiento de la partir de allí comenzaron a aparecer diferen- en este procedimiento se elimina la Capa de miopía y el astigmatismo2. Treinta años mas tes publicaciones haciendo énfasis sobre esta Bowman y se ha establecido el riego de pro- tarde otros autores demostraron que el pro- complicación26,27,28,29,30. ducir una protrusión hacia delante de la córnea cedimiento terminaba casi siempre con una central50. No obstante se han reportado casos descompensación de la cornea3. El procedi- Fisiopatología en los que se puede producir una ectasia sólo miento fue abolido casi totalmente después con el paso del microqueratotomo, después 4 de la aparición de estos artículos . Fyodorov Uno de los conceptos más difundidos de abortar el procedimiento LASIK, es decir introdujo en 1979 la queratotomía radial pero para entender el comportamiento de la cór- sin utilizar la fotoablación51. El espesor del limitada únicamente a la parte anterior de la nea y evitar complicaciones de este tipo en corte del microqueratomo no siempre es tan córnea con resultados que revolucionaron y cirugía refractiva ablacional es la conocida Ley exacto como se supone, puede haber casos en masificaron el concepto de la cirugía refrac- de espesores introducida por Barraquer que los que el paso del equipo automatizado haga tiva, muchos años antes concebida por José demuestra que al extraer tejido en la periferia cortes más gruesos de lo planificado, dejando 31 Ignacio Barraquer en Colombia, bajo el térmi- se produce una protrusión del tejido central . lechos muy delgados que sean la causa de la 5,6 no de Queratomileusis in situ . Igualmente se ha tratado de establecer cuál es ectasia post-operatoria52. Parte de este fenó- Poco tiempo más tarde después de su in- la cantidad mÍnima de tejido que debe dejarse meno fue utilizado por Ruíz cuando describió troducción en Rusia, Leo Bores la popularizó en el lecho para prevenir la ectasia pero existen una técnica para corregir la hipermetropía y la 7 en los Estados Unidos y pronto comenzaron muchas fórmulas que van desde dejar lechos presbicia53. 32 33 a aparecer artículos que demostraban los de 200μ , 200μ a 250μ y otros mas conser- Aunque existen en la literatura reportes riesgos de esta cirugía entre ellos la posibi- vadores creen que no se deben dejar espeso- que mencionan los beneficios del LASIK para 34 lidad de producir hipercorrecciones, rupturas res por debajo del corte menores de 318μ . miopías altas hasta de 20 dioptrías, sin que 8,9,10 11,12,13 tardias y ectasias . Hoy en día prácti- El espesor corneano preoperatorio y las se mencionen ectasias como una complica- camente ha desaparecido la queratotomía ra- formas topográficas atípicas sugestivas de ción54,55,56, en la actualidad se cree que los dial del arsenal quirúrgico entre los cirujanos queratocono frustro deben ser factores exclu- limites de la cirugía ablativa no deben sobre- 14,15 refractivos . yentes de cualquier tipo de cirugía ablativo pasar las 10 dioptrías y siempre vigilantes a 35 La queratomileusis in situ mediante con- con Excimer laser . Para Guirao estos facto- descartar aquellos casos con la mínima sos- gelación para modelaje de la córnea tal como res no son los únicos que se deben tener en pecha clínica o topográfica de posible quera- la ideo JI Barraquer, fue por muchos años cuenta, pues hay muchos otros detalles que tocono incipiente o frustro57,58. Así como hay privilegio de pocos cirujanos en el mundo a pueden influir como son la presión intraocular, cirujanos que no observaron ectasias después 16 pesar de sus buenos resultados , hasta que las fórmulas del modulo de Young, y el perfil de remover considerables cantidades de teji- 17,18 36 Theo Seiler y Mc Donald en 1990 , basa- de la ablación . Vinciguerra insite en evaluar do, artículos recientes reportan esta complica- dos en los descubrimientos de Trokel sobre preoperatoriamente el índice de asfericidad ción en ojos que previamente se consideraron 37 las aplicaciones del Excimer Laser en el ojo19 como un factor determinante . Aun se des- sin riesgos de acuerdo a las normas actuales y describieron las primeras cirugías fotorefrac- conoce cual es el verdadero papel que ejerce que al final se complicaron presentando ecta- tivas20, posteriormente Pallikaris modificó la la presión intraocular en la etiología de las sias en forma inexplicable59. 38 técnica mediante la creación de un colgajo y ectasias . Con la introducción del Orbscan En la actualidad con la introducción de los la remoción de áreas de estroma de 6.0 a 9.0 y otros equipos que procesan las imágenes lentes fáquicos en cámara anterior o posterior, mm en diámetro y más de 140 um en espesor de la superficie, espesor y curvatura de la es posible que las altas miopías tengan no sólo y bautizó el procedimiento21. córnea, se le ha dado gran importancia al un mejor pronostico visual con córneas mas La combinación de todas estas innovado- análisis de la curva posterior y su índice que fisiológicas sino que el riesgo de ectasias se ras tecnologías dio nacimiento a un técnica cuando es mayor de 30 debe ser un factor aboliría60. Aun hay autores que insiten en corre- que se denominó LASIK (Laser-Assisted in- de riesgo que puede terminar en queratectasia gir altas miopías con Láser proponiendo abla- 39,40,41,42,43 Situ Keratomileusis o Laser intrastromal ke- postoperatoria . ciones combinadas entre el lecho y el flap61.

PAN-AMERICA : 9 REVIEW

Entre las posibles causas de ectasias se TRATAMIENTO resis corneana y el uso de la Riboflavina con sugiere el debilitamiento de la córnea anterior Cuando se diagnostica una ectasia des- fotoestimulación se abre una nueva posibilidad que ocurre por disrupción de la capa de Bow- pués de cirugía refractiva, la calidad y cantidad de mejorar el estado de las córneas antes de man que se asocia a un encurvamiento de la de visión del enfermo comienza a deteriorarse acudir al transplante de córnea73. Estudios re- córnea central. A Bron ha demostrado que las y hay que tomar medidas inmediatas. La forma cientes inducen que el uso de prostaglandinas 100-200 um anteriores de la córnea son mu- más exacta de devolver el máximo de visión puede modificar también la estructura del co- cho más compactas que el resto del estroma son los lentes de contacto, siempre y cuando lageno corneano74. y van a ser por lo tanto más resistentes a la una de las razones que consideró el paciente Los nuevos conceptos sobre histeresis de deformación mecánica que el estroma poste- para decidirse a cirugía no haya sido la incon- la córnea y mejores conocimientos sobre la fi- rior62. Berlau encontró mediante estudios con formidad o la incapacidad para adaptarse a siología de la córnea, continuaran ayudando a microscopía confocal diferencias entre la dis- ellos67,68. Otra opción descrita por primera vez evitar los casos de iatrogenia en cirugía refrac- tribución de los queratocitos dependiendo de por Alio y otros autores, es el uso de implan- tiva con la inducción de ectasias75,76. En defini- la edad y de su localización en el espesor de la tes intraestromales, asumiendo que los espe- tiva podemos concluir que el comportamiento córnea63. La producción de ectasia como com- sores de la córnea lo permitan69,70,71. de la córnea después de la cirugía refractiva plicación después de cirugía LASIK hiperme- Cuando estas medidas no son suficientes aun no se ha clarificado completamente y que trópica se ha explicado histopatológicamente o inaceptables por la persona no queda otra el comportamiento de la misma después de la por la aparación de un anillo grueso epitelial en solución que acudir al transplante de córnea, cirugía ablativa es impredecible. Para evitar al la periferia64. Se ha demostrado que estas ca- los primeros reportes de casos tratados apa- máximo las ectasias postoperatorias se deben racterísticas influyen en la hidratación corneal recen en la literatura a partir de. La querato- extremar las medidas de selección preopera- y que cada cambio va a tener repercusión en el plastia lamelar es sin lugar a duda una de las toria, mediante una clara ananmesis sobre la poder refractivo de la córnea sobretodo cuando medidas quirúrgicas más conservadoras, pues evolución individual del defecto refractivo de esta se adelgaza65,66. evita las posibles complicaciones y el largo cada paciente y la utilización meticulosa de los postoperatorio de las técnicas penetrantes72. exámenes clínicos preoperatorios. Con la introducción del concepto de la histe-

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10 : PAN-AMERICA julio 2007 months after LASIK for correction of myopia and asymmetric astigmatism. 52. Ruiz LA, Rowsey J. In-Situ keratomileusis. Invest Ophthalmol Vis Sci. J Cataract Refract Surg. 2003;29:1222-5. 1988, 29: 392. 29. Randleman JB, Russell B, Ward MA, Thompson KP, Stulting RD. Risk 53. Astudillo IM, Ortiz CI. Combined laser in situ keratomileusis and pho- factors and prognosis for corneal ectasia after LASIK. Ophthalmology. 2003; torefractive keratectomy for extreme myopia. J Refract Surg. 1999 ;15:58-60. 110:267-75. 54. Marinho A; Pinto MC; Pinto R; Vaz F; Neves MC LASIK for high myo- 30. Lifshitz T, Levy J, Klemperer I, Levinger S. Late bilateral keratectasia pia: one year experience. Ophthalmic Surg Lasers, 1996 May, 27:5 Suppl, after LASIK in a low myopic patient. J Refract Surg. 2005;21:494-6. S517-20. 31. Barraquer JI. Basis of refractive keratoplasty-1967. Refract Corneal 55. Chayet AS, Assil KK, Montes M, Espinosa-Lagana M, Castellanos A, Surg. 1989 May-Jun; 5(3):179-93. Tsioulias G. Regression and its mechanisms after laser in situ keratomileusis 32. Wang Z, Chen J, Yang B. Posterior corneal surface topographic changes in moderate and high myopia. Ophthalmology. 1998 ;105:1194-9. after laser in situ keratomileusis are related to residual corneal bed thickness. 56. Sharma N, Singhvi A, Sinha R, Vajpayee RBReasons for not performing Ophthalmology. 1999; 106:406-9. LASIK in refractive surgery candidates. J Refract Surg. 2005 ;21:496-8. 33. Probst LE, Machat JJ. Mathematics of laser in situ keratomileusis for 57. Amoils SPDeist MB, Gous P, Amoils PM. Iatrogenic keratectasia after high myopia. J Cataract Refract Surg. 1998; 4:190-5. laser in situ keratomileusis for less than -4.0 to -7.0 diopters of myopia. J. 34. Esquenazi S. Comparison of laser in situ keratomileusis and automated Cataract Refract Surg 2000; 26: 967-977. lamellar keratoplasty for the treatment of myopia. J Refract Surg. 1997 Nov- 58. Klein SR, Epstein RJ, Randleman JB, Stulting RD. Corneal ectasia after Dec;13(7):637-43. laser in situ keratomileusis in patients without apparent preoperative risk fac- 35. Lafond G. Bazin R, Lajoie C. Bilateral severe keratoconus after lasik tors. Cornea. 2006 ;25:388-403. in situ keratomileusis in a patient with forma fruste keratoconus. J Cataract 59. Chang DH, Davis EA. Phakic intraocular lenses. Curr Opin Ophthalmol. Refract Surg 2001; 27: 1115-1123. 2006 ;17:99-104. 36. Guirao A.J Refract Surg. 2005 Mar-Apr;21(2):176-85 Theoretical elastic 60. Joo MJ, Kim YN, Hong HC, Ryu DK, Kim JH. Simultaneous laser in situ response of the cornea to refractive surgery: risk factors for keratectasia. J keratomileusis on the stromal bed and undersurface of the fl ap in eyes with Refract Surg. 2005; 21:176-85. high myopia and thin corneas. J Cataract Refract Surg. 2005 ;31:1921-7. 37. Vinciguerra P, Camesasca FI. Prevention of corneal ectasia in laser in situ 61. Bron AJ. The architecture of the corneal stroma [editorial]. Br J Oph- keratomileusis J Refract Surg. 2001; 17(2 Suppl):S187-9. thalmol 2001; 85: 379-381. 38. Arciniegas A, Amaya LE. Mechanical analog for the study of the internal 62. Berlau J.Becker H, Stave J et al. Depth and age dependent distribution forces of the eye. Ophthalmologica. 1980; 180:212-5. of keratocytes in healthy human corneas; a study using scanning slit confocal 39. Seitz B, Torres F, Langenbucher A, Behrens A, Suarez E. Posterior cor- microscopy in vivo. J Cataract Refract Surg 2002; 28: 611-616. neal curvature changes after myopic laser in situ keratomileusis. Ophthalmol- 63. Philipp WE, Speicher L, Gottinger W. Histological and immunohisto- ogy. 2001; 108:666-72 chemical fi ndings after laser in situ keratomileusis in human corneas. J Cata- 40. Marcos S, Barbero S, Llorente L, Merayo-Lloves J. Optical response to ract Refract Surg. 2003 ;29:808-20. LASIK surgery for myopia from total and corneal aberration measurements. 64. Turrs R, Friend J, Reim M, Dohlman CH. Glucose concentration and Invest Ophthalmol Vis Sci. 2001 ;42(:3349-56. hydration of the corneal stroma. Ophthalmic Res 1971; 2: 253-260. 41. Twa MD, Roberts C, Mahmoud AM, Chang JS Jr.Response of the pos- 65. Fatt I, Harris MG. Refractive Index of the cornea as a function of thick- terior corneal surface to laser in situ keratomileusis for myopia. J Cataract ness. Am J Optom Physiol Opt 1973; 50: 383-386. Refract Surg. 2005; 31:61-71. 66. O’donnell C, Welham L, Doyle S.Contact lens management of keratec- 42. Rao SN, Raviv T, Majmudar PA, Epstein RJ. Role of Orbscan II in tasia after laser in situ keratomileusis for myopia. Eye Contact Lens. 2004 screening keratoconus suspects before refractive corneal surgery. Ophthal- ;30:144-6. mology. 2002 ;109:1642-6. 67. Renesto Ada C, Lipener C. Contact lens fi tting after refractive surgery. 43. Ucakhan OO, Ozkan M, Kanpolat A. Corneal thickness measurements Arq Bras Oftalmol. 2005 Jan-Feb; 68(1):93-7. in normal and keratoconic eyes: Pentacam comprehensive eye scanner versus 68. Alio J, Salem T, Artola A, Osman A.Intracorneal rings to correct cor- noncontact specular microscopy and ultrasound pachymetry. J Cataract Re- neal ectasia after laser in situ keratomileusis. J Cataract Refract Surg. 2002 fract Surg. 2006 Jun;32(6):970-7. ;28:1568-74. 44. Amoils SP, Deist MB, Gous P, Amoils PM. Iatrogenic keratectasia after 69. Kymionis GD, Siganos CS, Kounis G, Astyrakakis N, Kalyvianaki MI, laser in situ keratomileusis for less than -4.0 to -7.0 diopters of myopia. J Cata- Pallikaris IG.Management of post-LASIK corneal ectasia with Intacs inserts: ract Refract Surg. 2000 ;26:967-77. one-year results. Arch Ophthalmol. 2003 ;121:322-6. 45. Argento C, Cosentino MJ, Tytiun A, Rapetti G, Zarate JCorneal ectasia 70. Pokroy R, Levinger S, Hirsh A.Single Intacs segment for post-laser in situ after laser in situ keratomileusis. J Cataract Refract Surg. 2001 ;27:1440. keratomileusis keratectasia. Cataract Refract Surg. 2004;30:1685-95. 46. Rao SN,Epstein J. Early onset ectasia following laser in situ keratomi- 71. Bilgihan K, Ozdek SC, Sari A, Hasanreisoglu B. Excimer laser-assisted leusis: case report and literature review. J Refract Surg 2002; 18: 177-184. anterior lamellar keratoplasty for keratoconus, corneal problems after laser Comaish IF Lawless MA.. Progressive post-LASIK keratectasia; biomechani- in situ keratomileusis, and corneal stromal opacities. J Cataract Refract Surg. cal instability or chronic disease process? J Cataract Refract Surg2002; 28: 2006 ;32:1264-9. 2206-2213. 72. Kohlhaas M, Spoerl E, Speck A, Schilde T, Sandner D, Pillunat LE. [A 47. Piccoli PM, Gomes AA, Piccoli FV. Corneal ectasia detected 32 months new treatment of keratectasia after LASIK by using collagen with ribofl avin/ after LASIK for correction of myopia and asymmetric astigmatism. J Cata- UVA light cross-linking] Klin Monatsbl Augenheilkd. 2005 ;222:430-6. ract Refract Surg. 2003 Jun;29(6):1222-5. 73. Liu Y, Yanai R, Lu Y, Hirano S, Sagara T, Nishida T. Effects of anti- 48. Randleman JB, Russell B, Ward MA, Thompson KP, Stulting RDRisk glaucoma drugs on collagen gel contraction mediated by human corneal fi bro- factors and prognosis for corneal ectasia after LASIK. Ophthalmology. 2003 blasts. J Glaucoma. 2006 ;15:255-9. ;110:267-75. 74. Luce DA. Determining in vivo biomechanical pro-perties of the cornea 49. Miyata K, Kamiya K, Takahashi T, Tanabe T, Tokunaga T, Amano S, with an ocular response analyzer. J Cataract Refract Surg. 2005 ;31:156-62. Oshika TTime course of changes in corneal forward shift after excimer laser 75. Randleman JB Post-laser in-situ keratomileusis ectasia: current under- photorefractive keratectomy. Arch Ophthalmol. 2002; 120:896-900. standing and future directions. Curr Opin Ophthalmol. 2006 ;17:406-12. 50. Haw WW, Manche EE. Iatrogenic keratectasia after a deep pri- mary keratotomy during laser in situ keratomileusis. Am J Ophthalmol. 2001;132:920-1. 51. Spadea L, Palmieri G, Mosca L, Fasciani R, Balestrazzi E. Latro- genic keratectasia following laser in situ keratomileusis. J Refract Surg. 2002;18:475-80.

PAN-AMERICA : 11 CLINICAL SCIENCES Factores de crescimento na retinopatia da prematuridade Growth factors and retinopathy of prematurity

Sofi a Almada1MD, Duarte Amado1MD, João Paulo Cunha1MD, Margarida Marques1MD 1. Serviço de Oftalmologia - Hospital de Santo António dos Capuchos, Centro Hospitalar de Lisboa, Zona Central Alameda de Santo António dos Capuchos, 1500 Lisboa, Portugal. Please address all correspondence to Sofi a Almada at the above address or email sofi [email protected]

Resumo the authors have made a search of published dada a sua pertinência, dois artigos de revisão INTRODUÇÃO: A retinopatia do prematuro articles on Medline and Pubmed since Janu- e desasseis artigos de investigação. continua a ter especial atenção dada a morbi- ary 2000 in English, Portuguese and Spanish lidade que apresenta a longo prazo e também a using these keywords: prematurity, retino- RESULTADOS: quantidade de recém-nascidos cada vez mais pathy, oxigenotherapy, neovascularization, O globo ocular e seus anexos começam a prematuros que os avanços científicos conse- growth factor. They also make manual search formar-se cedo no embrião humano. Uma das guem fazer sobreviver. Hoje em dia além do on books of ophthalmology, paediatrics and primeiras estruturas é o placóide cristalino controlo da oxigenoterapia e laserterapia co- embryology. RESULTS: They selected two que aparece aos 22 dias de vida intra-uterina meçam a querer-se incluir novos tratamentos review articles and sixteen investigation ar- como resultado da invaginação da ectoderme. usando os próprios factores promotores da ticles over hundred and ten that were found. Às cinco semanas forma-se a vesícula óptica normal vascularização retiniana. OBJECTIVO: CONCLUSION: The advance in the unders- e às sete semanas aparecem os vasos hialoi- fazer uma breve revisão do que foi publicado tanding of neovascularization seams to have deus para nutrir as novas estruturas que se es- sobre os vários factores promotores e inibido- practical application in a near future not only tão a formar. A retina começa a tomar forma a res da vascularização. MÉTODOS: Foi efec- on prematurity but also in others disease like partir das 15 semanas mas só ao oitavo mês de tuada uma pesquisa de artigos publicados na diabetic retinopathy or DMLI. vida intrauterina é que as camadas retinianas base de dados Medline/Pubmed desde Janei- Palavras chave: retinopatia,VEGF, PEDF, IGF, Epo, Radicais são reconhecíveis. Quanto à vascularização da ro de 2000, em língua inglesa, portuguesa ou livres de O2, MMA retina, esta tem origem nos vasos hialoideus espanhola, usando as palavras chave: prema- Key words: retinopathy, VEGF, PEDF, IGF, Epo, O2 free radicals, (que depois sofrem apoptose) e começa na turity, retinopathy, oxigenotherapy, neovascu- MMA mesma altura que se inicia a formação das ca- larization, growth factor. Foi também realizada madas da retina e só termina ao 10º mês pós- pesquisa manual em livros de Oftalmologia, INTRODUÇÃO: concepção (portanto no primeiro mês de vida Pediatria e Embriologia. RESULTADOS: Dos Os próprios factores promotores e ini- extra-uterina). A vascularização retiniana tem cento e dez artigos encontrados foram se- bidores da normal vascularização retiniana a particularidade de se centrar/iniciar no nervo leccionados 2 artigos de revisão e dezasseis podem ser usados no controlo ou tratamento óptico. Centrando-se na papila, está “descen- artigos de investigação que serviram de base de várias doenças que cursam com neovascu- trada” em relação ao eixo anteroposterior do a este artigo. CONCLUSÕES: Os avanços do larização, nomeadamente retinopatia diabética globo ocular, de que resulta que a vasculari- conhecimento nesta área da vascularização ou DMLI. No caso particular dos prematuros zação termina primeiro nos quadrantes nasais tem aplicação prática num futuro próximo, não a dificuldade do tratamento usando inibidores (mais ou menos no oitavo mês, ainda intrau- só nesta patologia como em outras em que há dos factores de crescimento é o equilíbrio que terino) e só depois nos temporais (no décimo neovascularização, nomeadamente retinopatia tem que existir entre a quantidade de factores mês – já extrauterino)1. diabética ou DMLI. promocionais e factores inibidores, pois nos O estímulo para o início da angiogénese é prematuros a vascularização normal ainda não a hipóxia. Assim começa uma “onda de vas- Abstract está completa e essa não pode ser inibida. cularização” que depende do equilíbrio entre INTRODUCTION: Because of long time mor- factores promotores e inibidores da vascula- bility and the incrising number of premature MÉTODOS: rização. As células ganglionares e do epitélio newborn that survive, rethinophathy of prema- Efectuamos uma pesquisa de artigos pu- pigmentar produzem PEDF (factor derivado do turity still is a special disease to study. Nowa- blicados na base de dados Medline/Pubmed epitélio pigmentar), as células do endotélio days more than oxigenotherapy or lasertherapy desde Janeiro de 2000 em língua inglesa, por- vascular produzem VEGF (factor de cresci- some new treatments using growth factors that tuguesa ou castelhana, usando as palavras cha- mento do endotélio vascular) e IGF (factor de normally promote the normal vascularization ve: prematurity, retinophathy, oxigenotheraphy, crescimento insulina-like), e a matriz extrace- are arising. PURPOSE: the authors make a neovascularization, growth factor. Foi também lular é responsável pela produção de metalo- review of published articles about the growth realizada pesquisa manual em livros de Oftal- proteínas. Todos estes factores são essenciais factors that promote and downregulate retinal mologia, Pediatria e Embriologia. Dos cento e para o aparecimento e manutenção de vasos vascularization. MATERIAL AND METHODS: dez artigos encontrados foram seleccionados, normais em localização normal (fig 1).

12 : PAN-AMERICA julio 2007

No prematuro a vascularização retiniana também tem início por volta das 15 semanas de vida intrauterina e em resposta ao mesmo estímulo de hipóxia. Mas a partir do momento em que o bébé nasce e se começa a suple- mentação com O2 deixa de haver hipóxia e começam as diferenças. A angiogénese no prematuro pode então dividir-se em duas fases para melhor compreensão2,3. Numa primeira fase (fig 2) forma-se retina avascular pois a oxigenoterapia basta para as necessidades do tecido que se está a formar. Numa segunda fase (fig 3), quando come- ça a haver redução/flutuações do suplemento de O2 existe hipóxia. Há de novo necessida- de de mais angiogénese pois toda a retina avascular que se formou entra em sofrimento. Nesta fase, em mais de 90%3 dos casos re- toma-se a vascularização normal e continua a maturação do aparelho visual. Nos outros casos a hipóxia que se inicia quando se dimi- nui a oxigenoterapia leva a um estímulo exa- gerado de produção de factores promotores da angiogénese - VEGF, PEDF, IGF, Epo, que originam neovasos (com endotélio permeável, Figura 1: com maior capacidade migrante e capazes de Angiogénese normal. invadir o vítreo). O bébe prematuro está sujeito a outras factores mais importantes são: VEGF, PEDF, xia. É o principal antagonista do VEGF, é o anti patologias além da retinopatia: Hemorragia IGF, Epo, Radicais livres de O2 e metalopro- angiogénico mais potente9,10 que se conhece. intraventricular, Sepsis, Enterocolite necroti- teínas (MMA). Tem também acção neurotrófica e neuropro- 4,1 zante, Displasia broncopulmonar cuja pro- O Factor de Crescimento do Endotélio tectora11. A sua acção neurotrófica manifesta- babilidade aumenta com o baixo peso, baixa Vascular (VEGF) é sintetizado pelo epitélio se pela capacidade de inibir a migração de idade gestacional, flutuação da oxigenotera- pigmentar e endotélio. É o principal pro- células endoteliais para os compartimentos pia e transfusões. motor da angiogénese. Activa a formação avasculares do olho (vítreo, córnea, humor Em relação à retinopatia do prematuro é das células do endotélio vascular e activa aquoso, camada nuclear externa). Curiosa- aceite que os principais factores de risco são genes antiapoptóticos, tendo por isso um mente há estudos12 que mostram que quan- a idade gestacional, o baixo peso e as flutua- papel relevante não só na génese mas tam- do se faz uma punção controlada da câmara ções de oxigénio. bém na manutenção dos vasos sanguíneos vítrea este factor aumenta na camada de Esta patologia foi referida pela primeira (indirectamente inibe a apoptose dos vasos células ganglionares, atenuando a resposta vez por Terry, em 1942 que a designou por recém-formados). Tem 5 isoformas conhe- inflamatória e a neovascularização. fibroplasia retrolenticular. Nos anos 50 foi cidas8 e há dois receptores8 na membrana O factor de crescimento insulina like associada a sua génese ao tratamento com das células do endotélio vascular: o VEGFR (IGF) é necessário para promover a função oxigénio. Finalmente nos anos 80 a doença 1 ou Flt – que é activado selectivamente máxima do VEGF13, actua como se fosse foi estadiada em doença limiar, pré-limiar pelo PlGF (factor de crescimento da placen- um co-factor. Quando existe abaixo do nível tipo 1 e pré-limiar tipo 2. Para o estudo desta ta) e o VEGRF 2 ou Flk9. O maior estímulo normal o VEGF acumula-se no vítreo e pára doença são de referência, o estudo ETROP5, para a sua produção é a hipóxia celular, e a angiogénese. Após a situação de hipóxia, CRYO-ROP6 e o STOP-ROP3. O primeiro con- a activação pelos receptores PlGF e IGF; a se o IGF aumentar lentamente e atingir o cluiu que ao invés de vigilância, a instituição produção é inibida pela hiperóxia. Quando nível normal a função do VEGF é normal, de tratamento precoce, diminui as conse- há hipóxia e o estímulo para a sua produção se houver um aumento rápido de IGF os ní- quências a longo prazo. Os estudos CRYO- é a activação pelo PlGF, há manutenção dos veis de VEGF aumentam acima do normal e ROP e STOP-ROP mostram os resultados níveis normais de VEGF não havendo neo- há formação de neovasos. Há estudos que quando se usa como tratamento a crioterapia vascularização. Além disso o factor derivado mostram que o nível sérico de IGF pode ser e quando se faz um controlo mais apertado da da placenta (PlGF) pode ser injectado no preditivo do aparecimento de ROP14. Nesse oxigenoterapia. vítreo8 com intuito terapêutico, para evitar o caso além da idade gestacional e do baixo Em termos de classificação da doença, aparecimento de neovasos2,8. peso também o baixo nível sérico de IGF se- há 3 vertentes que são consideradas: a locali- O Factor Derivado do Epitélio Pigmentar ria um factor de risco para ter ROP. zação, a extensão e a fase ou estádio7. (PEDF) é sintetizado pelo epitélio pigmentar A eritopoetina é um factor hematopoetico Em relação à angiogénese retiniana, (que e células ganglionares. O estímulo para a sua e angiogénico mas também neuroprotector e está alterada na retinopatia do prematuro) os produção é a hiperóxia e é inibido pela hipó- antiapoptótico15. A sua existência promove

PAN-AMERICA : 13 CLINICAL SCIENCES

a manutenção dos vasos recém-formados e impede a degenerescência das células da 1ª fase neuroretina15. A retina é muito sensível aos radicais livres de oxigénio principalmente no recém– nascido quando o controlo do fluxo sanguí- neo é imaturo, não havendo alterações do tónus vascular consoante a menor ou maior pressão de O216. Além disso a retina tem bai- xos níveis de antioxidantes capazes de neu- tralizar os redicais livres e é rica em ácidos gordos poliinsaturados que são o alvo desses radicais16. Ora na primeira fase da retinopatia do prematuro quando há oxigenoterapia for- mam-se muitos radicais livres que não são depois neutralizados e desencadeiam reac- ções que levam à destruição das células en- doteliais, entre outras. Há estudos pioneiros17 que apontam o tratamento tópico com um antiinflamatório como uma terapêutica válida na ROP, com base no papel dos radicais livres neste processo patológico. As metaloproteínas são proteinases da matriz extracelular produzidas principalmente Figura 2: pelas células endoteliais. São 14 enzimas das Primeira fase de angiogénese no prematuro. quais as tipo 2 e 9 degradam colagéneo IV, que existe na matriz extracelular. Tem como função “abrir caminho” na matriz extracelular para que os novos vasos se possam desen- volver. Há estudos feitos em ratinhos18 que mostram que a deficiência em MMP2 diminui a neovascularização da retina.

CONCLUSÕES: De todos os artigos seleccionados pode concluir-se que muitos dos factores modula- dores da angiogénese podem usar-se como 2ª fase terapêutica. Neste momento já há alguns fármacos que modulam estes factores. Os inibidores selectivos para o receptor 1 do VEGF po- dem ser usados em patologias em que há neovascularização no adulto. No prematuro, não se pode inibir por completo os factores angiogénicos pois são necessários para a angiogénese normal (o importante é o equi- líbrio entre os vários factores). Em relação às metaloproteínas há também alguns inibidores (marimastat, batimastat) que neste momen- to são usados em oncologia para reduzir o tamanho de matástases. Os radicais livres podem ser controlados com antiinflamatório tópico (keterolac). Quanto ao PEDF seria im- portante encontrar um fármaco mimético, e em relação à Epo um inibidor. A investigação sobre factores de cres- Figura 3: Segunda fase de cimento angiogénicos e seus moduladores angiogénese no merece cada vez mais a nossa atenção, dadas prematuro. as suas implicações práticas.

14 : PAN-AMERICA julio 2007

BIBLIOGRAFIA

1. Ryan S J, Retina, second ed., Saint Louis: USA 2001 May 8; 98(10): 5804–5808. Mosby, 1994. 14. Villegas B.E., Fernandez M.F.,González 2. Keshet Eli, More weapons in the arsenal R., Gallardo G. J.M.; Valores de IGF-I séri- against ischemic retinopathy. J Clin Invest cos en la ROP. Buscando nuevas indicaciones 2001 Apr 15; 107(8): 945–946. para su sreening: Ar-chivos de la Sociedad 3. Supplemental Therapeutic Oxygen for Española de Oftalmologia, 2005 Abr; 4. Prethreshold Retinopathy of Prematurity 15. Morita M, Ohneda O, Yamashita T, (STOP-ROP). A randomized, controlled trial. Takahashi S, Suzuki N, Nakajima O, Kawau- I: Primary outcomes Pediatrics 2000; 105(2): chi S, Ema M, HLF/HIF-2 is a key factor in 295-310. retinopathy of prematurity in association with 4. Graziano RM, Leone RC, Problemas oftal- erythropoietin, European Molecular Biology mológicos mais frequentes e desenvolvimento Organization, 2003; 22(5): 1134-1146. visual do pré-termo extremo. J Pediatr (Rio 16. Hardy P, Beauchamp M, Sennlaub F, J) 2005; 81(1):95-100 . Gobeil F, Tremblay L, Mwaikambo B, Lacha- 5. Early Treatment for Retinopathy of Pre- pelle P, Chemtob S, New insights into the maturity Cooperative Group: Revised Indica- retinal circulation: infl ammatory lipid media- tions for the Treatment of Retinopathy of Pre- tors in ischemic retinopathy. Prostaglandins, maturity: Results of the Early Treatment for Leukotrienes and Essential Fatty Acids 2005 Retinopathy of Prematurity Randomized Tri- May;72(5):301-325. al Arch Ophthalmol 2003; 121: 1684-1694. 17. Avila-Vasquez M, Maffrad R, Sosa M, 6. Kyvlin JD, Biglan AW, Gordon RA, Dob- Franco M et al,Treatment of retinopathy of son V, Hardy RA, Palmer EA, Tung B, Gil- prematurity with topical ketorolac trometh- bert W, Spenser R, Cheng KP, Buckley E: amine: a preliminary study, BMC Pediatrics Early retinal vessel development and iris 2004 (http://www.biomedcentral.com/1471- vessel dilatation as factors in retinopathy of 2431/4/15), acedido em 13/05/2005. prematurity. Cryotherapy for Retinopathy 18. Kyoko OM, Tomoko U, Takeshi Y, Masa- of Prematurity (CRYO-ROP) Cooperative to H, Takeshi I, Ikuo M, Manabu M; Reduced Group. Arch Ophthalmol 1996, 114(2):150-4. Retinal angiogenesis in MMP-2-defi cient 7. Committee for the Classifi cation of Retinop- mice. Investigative Ophthalmology and visual athy of Prematurity. An international classifi - science, 2003 Dec; 44(12):5370-5375. cation system of retinopathy of prematurity. Arch Ophthalmol 1984; 102(8): 1130-1134. 8. McColm JR, Geisen P, Hartnett ME, VEGF isoforms and their expression after a single episode of hypoxia or repeated fl uc- tuation between hyperoxia and hypoxia: rel- evance to clinical ROP. Molecular Vision 2004; 10: 512-20. 9. Shih SC, Ju M, Liu N, Smith LE, Selec- tive stimulation o VEGFR-1 prevents oxy- gen-induced retinal vascular degeneration in retinopathy of prematurity. J Clin Invest 2003 Jul 1; 112(1):50-57. 10. Gao G, Li Y, Zhang D, Gee S, Crosson C, Ma JX, Unbalanced expression of VEGF and PEDF in ischemia-induced retinal neovascu- larization, Federation of European Biochemi- cal Societies Letters 2001; 489: 270-276. 11. Keshet Eli, Preventing pathological re- gression of blood vessels. J Clin Invest. 2003 Jul 1; 112(1):27-29 12. Sttit AW, Graham D., Gardiner T.A., Ocular woun-ding prevents pre-retinal neo- vascularization and upregulates PEDF ex- pression in the inner retina. Molecular Vision 2004; 10: 432-438. 13. Hellstrom A, Perruzzi C, Ju M, Engström E, Härd A, Liu JL, Low IGF-I suppresses VEGF-survival signaling in retinal endothe- lial cells: Direct correlation with clinical reti- nopathy of prematurity, Proc Natl Acad Sci

PAN-AMERICA : 15 CASE REPORT A Long-term Complication of Retinal Reattachment Surgery: Extrusion of the Exoplant

Chun Cheng Lin Yang1, M.D., M.Sc. Corresponding Author: 1. Unidad Nacional de Oftalmología, Division of Ophthalmic Chun Cheng Lin, M.D., M.Sc. Plastic and Orbital Surgery, Ophthalmology Department, Hospital 8tava Calle 5-64 Roosevelt de Guatemala, Universidad de San Carlos de Guatemala, Zona 11 Guatemala City, Guatemala. Guatemala City Guatemala, 01007 Email: [email protected]/ [email protected]

ABSTRACT (Figure 3) The left eye’s best corrected visual PURPOSE: To report a case of silicon exo- acuity was 20/20 with refraction of -7.00 -0.75 plant extrusion 10 years after scleral buckle *180. Anterior segment of this eye was nor- surgery. mal, and some laser scars at the inferior retinal METHODS: Case Report. periphery were the only positive findings dur- RESULTS: The patient agreed to the enuclea- ing the indirect funduscopy examination. tion of the right globe with the extruded Due to the constant pain that the patient scleral buckle, due to the symptoms of this experienced in this non functional eye with phthisical eye. the extruded buckle, enucleation was offe- DISCUSSION: Scleral buckle surgery has red to her. The patient readily accepted the a wide range of complications, either at the procedure. Oral ciprofloxacin at 500mg twice short- or long-term interval after the proce- daily, diclofenac at 50 mg three times a day, Figure 1: Right eye position in primary gaze. dure. Due to these, lifelong yearly follow up of and topical ciprofloxacin four times daily patients with scleral buckling implantation is were started on the patient for one week, justifiable and mandatory. before the surgical procedure. A classical enucleation was performed on the patient. INTRODUCTION The silicon band was tightly adhered to the The evolution of scleral buckle material sclera, and excess of fibrotic tissue around has come from absorbable autologous tissues the band was noticed in the enucleated to non-absorbable synthetic elements such as globe.(Figure 4) Two weeks after the surgery, silicon and hydrogels.2 Initially, the synthetic right eye prosthesis was fitted, and it has group was well tolerated by the patients. How- been well tolerated by the patient. ever, over time, a great spectrum of complica- tions associated with these explants has been DISCUSSION Figure 2: described in the literature.1-13 We report a case Ever since Schepens popularized the en- Extrusion of scleral buckle thru the conjunctiva in the superior temporal quadrant, view during slit lamp of scleral buckle explant extrusion ten years af- circling scleral buckle technique for retinal examination. ter retinal reattachment surgery and review the detachment surgery in the late 1950s1, the complications of synthetic buckle materials. scleral buckle material has evolved from using absorbable material such as dura mater or au- CASE REPORT togenous fascia lata to nonabsorbable synthet- A 35-years-old patient was referred to our ic agents including polyethylene tube, silicon center with history of profound ocular dis- rubber, silicon sponge, and hydrogels.2 charge and pain in her right eye for the last All the synthetic material used in retinal three months before consultation. She had reattachment surgery have initial acceptable retinal detachment surgery in her right eye tolerance by the patient. However, either in 10 years ago in another center. One year after the short- or long- term, complications could the retina procedure, the patient’s vision was be expected from these. Silicone explants, completely lost. On examination, the right eye either sponge or rubber, tend to manifest was fully adducted in primary gaze.(Figure1) complications earlier compared to hydrogels, The visual acuity was no light perception, and solid silicone (mean, 11 months), and sili- Figure 3: it was a phthisical eye with IOP of 1 mm Hg. cone sponge (mean, 19 months).3,4 The most Total corneal opacity, preventing evaluation of the posterior pole. Upon aperture of the lids, a fragment of the commonly reported problems for this group sclera buckle protruded thru the conjunctiva of of materials include: infection, foreign-body the superior temporal quadrant.(Figure 2) The sensation, strabismus, intraocular migration, eration, and rupture of conjunctiva with buckle anterior segment and posterior pole were not and conjunctival alterations such as, recurrent extrusion.1,6 And perhaps, the most unusual evaluable since the cornea was totally opaque. subconjunctival hemorrhage, cystoids degen- complication associated with silicone mate-

16 : PAN-AMERICA julio 2007

Figure 4: Enucleated right globe with tightly adhered scleral buckle 360 degree around the globe, showing also extensive fi brotic tissue around the buckle and conjunctiva. Figure 4: rial has been spontaneous cutaneous extru- Enucleated right globe with tightly adhered scleral buckle 360 degree around the globe, showing also extensive fi brotic tissue around the buckle and conjunctiva.. sion of exoplant.7,11,12 As for the hydrogels, their complications have been reported to manifest at an average gel scleral buckle simulating orbital tumor. quadrant. An alternative technique removal of of 10 years after the initial surgery.3,16 These Other orbital complications related to hydrogel extruded scleral buckle is cryoextraction after are related to extensive swelling of the im- scleral buckle material are prosthetic intoler- generous conjunctival opening.14 plants, due to their physical properties.2 The ance, clear or hematic orbital cyst, pseudo-or- Overall, independent of the material used most frequent problems associating hydrogel bital cellulitis, or pseudotumor.8,13 for scleral buckle surgery, the outcome of this scleral buckle material include: conjuncti- In our case, the extrusion of the scleral simple procedure is associated with multiple val bulging, implant migration, limitation of buckle material was obvious. The patient complications. These are time dependant. Our ocular movement leading to strabismus or agreed to the enucleation due to the painful case illustrates one of the long-term compli- diplopia, ocular pain, ocular inflammation, blind eye. If the eye had visual prognosis, the cations. Perhaps, a wise remainder in manag- protrusion of the buckle beneath the eyelids, recommended procedure is the removal of the ing any patient after scleral buckling implanta- extrusion of scleral buckle material associated extruded material in a operating room setting.8 tion is a lifetime yearly follow-up, as Schepens with its fragmentation, infection in a lower rate Removal of the buckle is difficult.9,16 Kearny et always defended.5,15 compared to silicone material, and rarely im- al.9 recommend a 360-degree conjunctival plant erosion in the eye with poor visual out- peritomy over small incision. To avoid grasp- come.2,4,5,8,9,10 Hydrogels are also associated ing and pulling on the element, they suggest with orbital complications. Recently, Shields cutting the buckle in each quadrant, and push- et al.3 reported 4 cases of expanding hydro- ing it through the fibrous tunnel to an open

REFERENCES

1. Hilton GF, Wallyn RH. The removal of thalmol 1983; 101:570-4. Transpalpebral extrusion of a silicone sponge scleral buckles. Arch Ophthalmol 1978; 96 7. Voegtle R, Laplace O, et al. Cutaneous ex- exoplant. Br J Ophthalmol 1991; 75:499-500. :2061-63. trusion of a silicone sponge exoplant. Retina 13. Braunstein RA. Complications of MI- 2. Hwang KI, Lim JI. Hydrogel exoplant frag- 2001;21:565-6. RAgel: pseudotumor. Arch Ophthalmol 2002 mentation 10 years after scleral buckling sur- 8. Bernardino CR, Mihora LD, Fay AM, et ;120: 228-9. gery. Arch Ophthalmol 1997; 115:1205-6. al. Orbital complications of hydrogel scleral 14. Le Rouic JF, Bejjani RA, Azan F, et al. 3. Shields CL, Demirci H, Marr B, et al. buckles. Ophthal Plast Reonstr Surg 2006; Cryoextraction of episcleral MIRAgel buckle Expanding MIRAgel scleral buckle simulat- 22:206-8. elements: a new technique to reduce fragmen- ing an orbital tumor in four cases. Ophthal 9. Kearney JJ, Lahey M, Borirakchanyavat tation. Ophthal Surg Lasers 2002; 33:237-9. Plast Reonstr Surg 2005; 21:32-8. S, et al. Complications of hydrogel explants 15. Schepens CL. Follow-up of successful 4. Le Rouic JF, Bettembourg O, D’Hermies used in scleral buckling surgery. Am J Oph- scleral buckling: how long? Ann Ophthalmol F, et al. Late swelling and removal of MIRA- thalmol 2004; 137:96-100. 1970; 2:126. gel buckles: a comparison with silicone inden- 10. Marin JF, Tolentino FI, Refojo MF, 16. Li K, Lim KS, Wong D. MIRAgel explants tations. Retina 2003; 23:641-6. Schepens CL. Long-term complications of fragmentation 10 years after scleral buckling 5. Roldan-Pallares M, del Castillo Saenz MAI hydrogel intrascleral buckling implant. surgery. Eye 2003; 17: 248-50. JL, et al. Long-term complications of sili- Arch Ophthalmol 1992; 110:86-8. cone and hydrogel explants in retinal reat- 11. Ozerturk Y, Bardak Y, Durmus M. An tachment surgery. Arch Ophthalmol 1999; unusual complication of retinal reattach- 117:197-210. ment surgery. Ophthalmic Surg Lasers 1999; 6. Lindsey PS, Pierce H, Welch RB. Remov- 30:483-4. al of scleral buckling elements. Arch Oph- 12. Winward KE, Johnson MW, Kronish JW.

PAN-AMERICA : 17 CHAIRMAN OF THE PAN-AMERICAN FOUNDATION BOARD

NATALIO IZQUIERDO, MD

Aprendiendo Liderazgo de los Personajes del Mago de Oz Dorothy became a leader by following the Yellow Brick Road S igamos a Dorothy en su camino para ver el Mago de Oz. Imaginemos que como hizo Dorothy. Los líderes hacen algo por sus organizacciones y sus el camino amarillo hacia la Ciudad Esmeralda tiene cinco escalones. pueblos. Esta es la escalera que describe Maxwell hacia la excelencia en el lide- De la audiencia con el Mago de Oz, hay dos cosas importantes que razgo. Para que sea fácil recordarla, cada escalón tiene una palabra que aprender. La primera trata sobre la integridad: que es un valor muy pre- comienza con la letra R. ciado para un líder. Los seguidores pierden su fé en los líderes cuando se Dorothy se convierte en líder cuando adquiere una posición Radian- descubre su falta de integridad. Todos conocemos líderes sin integridad te. Ella en la película adquiere los zapatos de color rubí. El tipo de en la historia y no debemos emularlos. En la película la voz y la imagen liderazgo que se adquiere por una posición, es decir por unos zapatos del mago eran parte de una farsa. El mago defraudó los personajes de que llenamos temporalmente, tiene sus desventajas. Primero que es la película, al igual que a los que estaban en el teatro. Un buen líder no un liderazgo temporáneo, como lo es una presidencia de una sociedad puede actuar como el Mago de Oz. Segundo, el olfato de Toto, el perro de profesional. Segundo es una posición envidiable. En la película del Mago Dorothy, descubrió la verdad sobre la farsa del mago. Toto representa la de Oz, la bruja deseaba tener esos zapatos. ¿Sabes quién quiere estar en intuición del líder. Los estudiosos piensan que los buenos líderes tienen tus zapatos? un buen olfato, o perspicacia y que además deben seguir sus instintos. En el camino, Dorothy se encuentra con el Espanta-pájaros. Este Cuarto, Dorothy ayudó a cada uno de sus acompañantes de una forma personaje representa un líder que cree no tener suficiente inteligencia. muy especial. Les ayudó a hacer sus sueños realidad. Les ayudó a adquirir Padece de miedo al fuego, que no es otra cosa que el fuego de preguntas las herramientas para poder alcanzar sus metas. Esto es lo que el Curso o de las luchas que damos los profesionales día a día. Dorothy comienza de Liderazgo hace por mi. Poco a poco nuestros maestros, van moldeando a mejorar como líder porque lo ayuda a creer en sí mismo. Además está nuestro carácter y nos convertimos un poco en ellos, cuando los imitamos nueva amistad nos demuestra, que siempre podemos aprender algo de o intercambiamos ideas. Por eso, Maxwell dice que los líderes crecen los demás, que son nuestros maestros y que es importante en nuestro cuando llegan a ser Reproductores de Líderes. En otras palabras, La camino buscar el consejo de los sabios. Dra. Zelia Correa quiso crear nuevos líderes en la Oftalmología y en cada Más adelante Dorothy se encuentra con el Hombre de Lata (Tin-man). uno de los participantes que se educa en el Curso de Liderazgo, ella Este personaje reconoce que carece de un corazón. En otras palabras, reproduce las buenas características y destrezas de un líder. él adolesce de pobre inteligencia emocional. Dorothy lo encuentra un Finalmente, a largo plazo, la gente comienza a sentir Respeto por sus poco rígido y lo ayuda aceitando sus piezas enmohecidas por el tiempo. líderes. Este respeto se convierte en un premio honorífico que ganan los Dorothy lo ayuda a ser más flexible (menos rígido) y por ende más sen- líderes que permanecen indoblegados a través del tiempo y los esfuerzos sible. Todos conocemos este tipo de líder rígido. La historia del mundo de la vida, a pesar de los fracasos, entre tantos éxitos. Este escalón me está plagada de líderes rígidos totalitarios. Como seres humanos, en recuerda a líderes como los doctores Picó, Berrocal, Townsend, Brennan y nuestras relaciones interpersonales tenemos que ser flexibles. Como lí- Maumenee entre otros. La gente los respeta por lo que son: magnánimes. deres tenemos que aprender a transar y buscar nuevas alternativas en La gente los respeta por sus obras magníficas. un mundo cambiante. Además un buen líder debe sentir pasión por su En conclusión, hay varios tipos de líderes, como vimos en la película profesión y sus gestas. del Mago de Oz. Hay cinco escalones en la escalera del liderazgo. La En el camino Dorothy y sus amigos encuentran el León-Cobarde. integridad es una cualidad muy importante para los líderes. Finalmente, Este personaje representa el líder que es tímido. En otras palabras, este “no hay nada como el hogar”, que es nuestra profesión y nuestra patria, es el líder discapacitado por sus miedos y su timidez. Esta dolencia para poner todas estas ideas en uso. la describimos hoy día como poca inteligencia social. Esta destreza es necesaria para establecer puentes de comunicación. Como líderes ******* tenemos que renovar alianzas viejas y crear alianzas nuevas. Imagine a ladder made out of yellow bricks, as we join the cast En el camino Dorothy ha dado su segundo paso en la escalera del members of the movie called The Wizard of Oz, on their way to Emerald liderazgo que es el de hacer Relaciones interpersonales. En esto nos City. For the purpose of this essay, the cast members of this movie re- ayuda la Asociación Panamericana de Oftalmología, ya que nos facilita el present various leader types. I firmly believe that Dorothy became an exce- poder establecer relaciones humanas con pares y líderes profesionales de llent leader following the yellow brick road. John Maxwell described a otros países. Los oftalmólogos deben apoyar las asociaciones profesio- ladder you must climb during your career, to become an excellent leader. nales nacionales e internacionales, ya que benefician a todos. I will paraphrase Maxwell’s idea to describe five steps needed to become En el clímax de la película Dorothy logra la entrevista con el Mago de a leader (5 words that start with an R). Oz, no sin antes tener que lidiar con el portero de la ciudad. En nuestras Dorothy became a leader as she acquired the red shoes. Her shoes gestas como portavoces y líderes, tenemos que aprender a bregar con may represent a position in the Board of your local Ophthalmic Society. I porteros, que pueden ser administradores o asesores. Entonces el tercer remember Dorothy’s ruby shoes made the witch feel green with jealousy. escalón es el de poder lograr algo por el grupo, el de obtener Resultados, Sometimes a leadership position has a limited time frame, and some

18 : PAN-AMERICA people tend to envy those in positions of power. In summary: the In conclusion, we have talked about various leader types, and first step in the ladder is having a position, and Radiate power. 5 easy steps to climb on the leadership ladder. Go for it! “There is On the way to Emerald City, Dorothy met Scarecrow. He no place like home”... to discover the leader within you. represents a leader with no brains (low IQ). He was insecure References and feared the fire. Needless to say, there are few physicians like Maxwell John C., Developing the Leader within You Scarecrow, as we are all very smart. However, you may always learn some more, or teach others. A continuing learning process is the cure for leaders like Scarecrow. Dorothy also met Tin-man. He represents a rigid leader, a dictator. He had no heart, or a low emotional IQ. Dorothy helped Tin-man by making him more flexible. As a leader you need to love your profession and be compassionate with others. Further, a good leader is very passionate about his quests. So as leaders we must work on our emotional skills. Further, we must convince others that our dreams may come true. Then Dorothy met the Cowardly Lion, who was insecure, and somewhat shy. He had no courage. In other words, he represents a leader who lacks social skills. As leaders we need to improve our social and communication skills. We must give others a pat in the back every once in a while. We must accompany others in their quests, in their moments of joy, and in their moments of sorrow. On her way to Emerald City, that is, on her quest for becoming an excellent leader, Dorothy made several friends. Therefore, the second step of the ladder is creating Relationships. We need to create new bridges, and remodel old bridges such as professional alliances. We all need to participate in the PAAO meetings! As she finally got to Emerald City with her new friends, she reached her goal, and helped others reach their goal. In other words, leaders help followers to reach a goal as a team, to follow the leader’s dream. She led the group to a final destination. To enter the city, she had to deal with the city’s Gatekeeper. We all know who the real life gatekeepers are: administrative personnel, advisors, among others. As she finally got an audience with the Wizard of Oz, Dorothy reached the third step on the ladder, that is, she had Results. On their audience with the Wizard there are two issues that are worth mentioning. First a word of advice: integrity is most precious to a leader. We all know leaders without integrity. People tend to lose their faith on leaders without integrity. The Wizard’s voice, and his magic tricks were a farce. Don’t you recall a feeling of deception as you discovered that the Wizard was a fraud? As leaders we most avoid being like the Wizard. Otherwise followers may loose their faith. Second, do you remember Toto? This dog with a wonderful olfactory sense represents a leader’s intuition. A leader needs to follow his intuitive thoughts, as intuition may lead leaders to find the truth. Fourth, Dorothy helped each member of the group in a very personal way. She helped them reach their goals, to acquire the tools they thought they did not have. She allowed them to become excellent leaders. This is exactly what the Curso de Liderazgo, the PAAO’s Leadership Course, did for me. In the Curso we become like Dr. Zelia Correa, among other leaders of the PAAO. That is why Maxwell calls this fourth step in the ladder Reproduction. We become like our mentors, and in a way our mentors live forever through us. Finally, in the long run, as a lifetime achievement award, people will respect good leaders. People love leaders for who they are, and what leaders represent. For this reason Maxwell states that the fifth step is Respect. This step reminds me of leaders like Dr. Picó, Berrocal, Townsend, Brennan and Maumenee among others.