DOCSLIB.ORG

Ultra-High Resolution Optical Coherence Tomography for Imaging the Anterior Segment of the Eye

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ultra-High Resolution Optical Coherence Tomography for Imaging the Anterior Segment of the Eye IMAGING ■ R E V I E W ■ Ultra-High Resolution Optical Coherence Tomography for Imaging the Anterior Segment of the Eye Jianhua Wang, MD, PhD; Mohamed Abou Shousha, MD; Victor L. Perez, MD; Carol L. Karp, MD; Sonia H. Yoo, MD; Meixiao Shen, MSc; Lele Cui, MD; Volkan Hurmeric, MD; Chixin Du, MD; Dexi Zhu, PhD; Qi Chen, MD; Ming Li, MD ABSTRACT INTRODUCTION Developments in optical coherence tomography Optical coherence tomography (OCT) is a non- (OCT) have expanded its clinical applications for ul- contact and non-invasive imaging modality based on tra-high resolution imaging of the anterior segment the Michelson interferometer.1,2 It has been widely of the human eye. This review presents the latest ad- used in ophthalmology since its development 20 years vances for imaging the anterior segment of the eye us- ago,1 mainly for imaging the posterior segment of the ing ultra-high resolution OCT (UHR-OCT). Unique eye, including the retina and optic nerve head.3-5 Many applications of UHR-OCT technology in clinical and commercially available OCT instruments have been basic scientific laboratory research are discussed and a extremely helpful in the diagnosis of retinal diseases5,6 summary of the results is provided. The authors fo- and for advancing our capability to research and docu- cused on the use of UHR-OCT for imaging of tear ment structural changes in the retina.7-9 In addition to dynamics, contact lens interactions with the corneal retinal imaging, the retinal OCT10,11 and prototype an- surface, and in vivo histological diagnosis of disorders terior segment OCT instruments2,12,13 were used to ex- of the cornea, as well as the future direction in this plore the anterior segment, mainly the cornea, anterior field. [Ophthalmic Surg Lasers Imaging 2011;42: chamber, and chamber angle.14 In 2005, a commer- S15-S27.] cially available anterior segment OCT (Visante; Carl From Bascom Palmer Eye Institute (JW, MAS, VLP, CLK, SHY, MS, LC, VH, CD, DZ, QC, ML), University of Miami, Miami, Florida; the School of Ophthalmology and Optometry (LC, DZ, QC, ML), Wenzhou Medical College, Wenzhou, Zhejiang, China; and the Department of Ophthalmology (CD), First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China. Originally submitted February 11, 2011. Accepted for publication February 25, 2011. Supported in part by grants from Vistakon, Allergan, Bausch & Lomb, CibaVision, CooperVision, and Alcon Research Laboratories, and by research grants from NIH Center Grant P30 EY014801 and Research to Prevent Blindness. The authors have no financial or proprietary interest in the materials presented herein. The authors thank Drs. Eduardo Alfonso and Carmen Puliafito for their support, and Dr. Britt Bromberg of Xenofile Editing for providing editing services for this manuscript. Address correspondence to Jianhua Wang, MD, PhD, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, 1638 NW 10th Avenue, McKnight Building–Room 202, Miami, FL 33136. E-mail: [email protected] doi: 10.3928/15428877-20110627-02 OPHTHALMIC SURGERY, LASERS & IMAGING · VOL. 42, NO. 4 (SUPPL), 2011 S15 IMAGING IMAGING Zeiss Meditec, Inc., Dublin, CA) was then produced and width with some of the instruments were enough to for anterior segment imaging.15 cover the entire anterior segment.2,14 In this review, we will focus on recent advances for With the recent advances in SD-OCT, which has a imaging the anterior segment of the eye using ultra-high resolution of approximately 5 µm, commercially avail- resolution OCT (UHR-OCT) with resolution below 5 able instruments for retinal scanning could also be used µm. Researchers including our group and companies to scan the anterior segment.31 These included the Cirrus have developed UHR-OCT devices that can image (Carl Zeiss Meditec, Inc.), RTVue (Optovue, Meridian- the anterior segment of the eye in a rapid and patient- ville, AL), Spectralis (Heidelberg Engineering, Dossen- friendly way, with a novel resolution of 1 to 3 µm.16-25 heim, Germany), 3D OCT (Topcon Medical Systems, In this review, we will provide a summary of our results Oakland, NJ), and Bioptigen SD-OCT (Bioptigen Inc., and other published studies using this technology and Research Triangle Park, NC) and others31,42,43 for imaging its unique applications in clinical and basic scientific human eyes. The scan width of approximately 3 to 6 mm laboratory research use. We will discuss how the UHR- for imaging the anterior segment limited some applica- OCT was used for imaging the tear dynamics,20,26,27 tions that demanded a wide scan width, such as imaging contact lens interactions with the corneal surface,26 and the upper and lower tear menisci simultaneously.20 in vivo histological diagnosis of disorders of the cor- The development of UHR-OCT has significantly nea.28 This will also include personal experiences based improved anterior segment imaging capabilities.16-19 on unpublished data using UHR-OCT. Finally, we will In 2001, Drexler et al. reported an image of a normal briefly discuss future directions in this field. human eye using approximately 2-µm axial resolution Although we understand that other published TD-OCT.18 This may be the first demonstration for works have reviewed the use of OCT to study the ante- imaging the Bowman’s layer with UHR-OCT.18 In rior segment, these have mainly covered time-domain 2004, Drexler reported 1-µm axial resolution OCT OCT instruments and high-resolution spectral-domain for imaging the cornea in vitro.17 In 2007, Christo- OCT (SD-OCT).15,29-32 It is important to mention poulos et al. reported the use of corneal UHR-OCT that, simultaneous with the development of UHR- for imaging tear film, corneal epithelium, Descemet OCT for imaging the anterior segment, extended scan membrane, and the endothelium.19 In this report, depth OCT has been developed also for imaging the the trauma with epithelial ingrowth by LASIK has anterior segment, including the anterior chamber and been visualized clearly.19 By using a light source with crystalline lens.33-35 However, the extended scan depth a broad bandwidth of more than 100 nm, ultra-high OCT is not within the scope of this summary. This resolution is achieved with a specifically designed review is focused on the latest clinical applications in spectrometer that detects the fringes collected from anterior segment imaging with UHR-OCT and pro- both reference and sample arms.7,19,20,22-24,26,28,44-47 vides the most recent update in the use of a novel and With a charge-coupled device line scan camera in “futuristic” way to image this part of the eye to add the spectrometer, the speed ranges normally from useful information to the field. 24K to 26K A-scans per second.7,22,23 With a com- plementary metal–oxide–semiconductor line scan UHR-OCT TECHNIQUE camera or ultra-high speed swept source, the speed can be much higher.25,48,49,50 Axial resolution is 2 to The first generation of OCT for imaging the anterior 4 µm in these UHR-OCT instruments.7,20,24,26,28,44-47 segment was the time-domain OCT (TD-OCT). It had Although some instruments have scan widths of ap- approximately 10- to 18-µm resolution and 2K A-scans proximately 5 mm,24 others have wider scan widths per second. The center wavelength was 1,310 nm in the of up to 12 mm.20 Apparently, there are two com- Visante,36 the SL-OCT (Heidelberg Engineering, Heidel- mercially available UHR-OCT devices, including the berg, Germany),37 and other prototypes.38-40 In addition, Bioptigen SD-OCT22,23 and Copernicus HR SOCT modified retinal TD-OCT instruments, such as the Stra- (Optopol Technology SA, Zawiercie, Poland).24 With tus (Carl Zeiss Meditec, Inc.), also were used to image the these commercial and prototype UHR-OCT instru- anterior segment.29,41 With TD-OCT, the speed was low ments, the tear film,20,26 tear meniscus,20 contact and resolution was not very high, although the scan depth lens,20,24,26,45,46 and corneal layers28,51-53 can be im- S16 COPYRIGHT © SLACK INCORPORATED IMAGING IMAGING Figure 1. Ultra-high resolution optical coherence tomography image of the central cornea with a PureVision (Bausch & Lomb, Rochester, NY) lens after instillation of artificial tears. The central cor- nea was imaged with 6-mm scan on the horizontal meridian. The image was taken immediately after lens insertion and instillation of one drop of artifi- cial tears. The epithelium, including the basal cell layer, and Bowman’s layer, are evident in addition to the pre-lens and post-lens tear films. Total cor- neal thickness was measured at 526 µm. Bars = 250 µm. (Reprinted with permission from Wang J, Jiao S, Ruggeri M, Shousha MA, Chen Q. In situ visualization of tears on contact lens using ultra- high resolution optical coherence tomography. Eye & Contact Lens. 2009;2:44-49.) aged, and the axial resolution is sufficient for clear age these is essential to precisely measure the thickness visualization of structures of interest (Fig. 1). Optical of the PLTF and PoLTF. UHR-OCT made it possible distortion of the OCT images needs to be corrected to directly visualize and calculate the tear film as long before the measurement is taken.54 However, we cited as it is thicker than 3 µm.20,26 In a previous study,26 these published and unpublished images, which are dynamic changes of the PLTF and PoLTF after instil- not optically corrected. The image correction has lation of artificial tears were investigated using UHR- been reported in the literature54,55 and the same pro- OCT.
Load more

Recommended publications
  • Qualified/Nonqualified Medical Expenses Under Health FSA/HRA Or HSA
    Qualified/Nonqualified Medical Expenses under Health FSA/HRA or HSA Below is a partial list of medical expenses that may be reimbursed through your FSA/HRA or HSA, including services incurred by you or your eligible dependents for the diagnosis, treatment or prevention of disease, or for the amounts you pay for transportation to get medical care. In general, deductions allowed for medical expenses on your federal income tax, according to the Internal Revenue Code Section 213 (d), may be reimbursed through your FSA/HRA or HSA. Some items might not be reimbursable under your particular health FSA or HRA if the FSA or HRA contains exclusions, restrictions, or other limitation or requirements. Consult your summary plan description (SPD) of the health FSA or HRA for guidance. If you have an HSA, you are responsible for determining whether an expense qualifies for a tax‐free distribution. Qualified Expenses (partial list) Acupuncture Insulin Alcoholism treatment Lactation consultant Ambulance Laser eye surgery, Lasik Artificial limbs Occlusal guards to prevent teeth grinding Artificial teeth Optometrist Bandages, elastic or for injured skin Organ donors Blood pressure monitoring device Orthodontia Blood sugar test kits and test strips Osteopath fees Breast Pumps Oxygen Chiropractor Prosthesis Cholesterol test kits Reading Glasses Contact lenses Stop‐smoking aids Crutches Telephone equipment to assist persons with Dental Services and procedures hearing or speech disabilities Dentures Television equipment to assist persons with Diabetic supplies
    [Show full text]
  • (Usually Oxygen) Burn Reaction Adds Energy to Effect • Steel Typical
    Reactive Fusion Cutting • When gas used reacts with gas (usually oxygen) burn reaction adds energy to effect • Steel typically 60% added energy • Titanium 90% added energy • However can reaction can chemically change the work face eg titanium gets brittle from oxygen • Cutting speed is increases with addition of oxygen Reactive Fusion Cutting Striations • Reactions create a burn front • Causes striations in material • Seen if the cut is slow Behavior of Materials for Laser Cutting • Generally break down by reflectivity and organic/inorganic Controlled Fracture and Scribing Controlled Fracture • Brittle materials vulnerable to thermal stress fracture • Heat volume: it expands, creates tensile stress • On cooling may crack • Crack continue in direction of hot spot • Mostly applies to insulators eg Sapphire, glass Scribing • Create a cut point in the material • Forms a local point for stress breakage • Use either a line of holes or grove Cold Cutting or Laser Dissociation • Uses Eximer (UV) lasers to cut without melting • UV photons 3.5 - 7.9 eV • Enough energy to break organic molecular bonds • eg C=H bond energy is 3.5 eV • Breaking the bonds causes the material to fall apart: disintigrates • Does not melt, chare or boil surface • eg ArF laser will create Ozone in air which shows the molecular effects Eximer Laser Dissociation • Done either with beam directly or by mask • Short Laser pulse absorbed in 10 micron depth • Breaks polymer bonds • Rapid rise in local pressure as dissociation • Mini explosions eject material Eximer Micromachining
    [Show full text]
  • Fluency of Laser and Surgical Downtime, Loss of Fixation, As Factors Related to the Precision Refractive
    112ARTIGO ORIGINAL Fluência do laser e tempo de parada cirúrgica, por perda de fixação, como fatores relacionados à precisão refracional Fluency of laser and surgical downtime, loss of fixation, as factors related to the precision refractive Abrahão da Rocha Lucena1, Newton Leitão de Andrade2, Descartes Rolim de Lucena3, Isabela Rocha Lucena4, Daniela Tavares Lucena5 RESUMO Objetivo: Avaliar a correlação da fluência e o tempo de parada transoperatória por perda de fixação, como fatores de hiper ou hipocorreções das ametropias pós-Lasik. Métodos: A idade variou entre 19 e 61 anos com média de 31,27 ± 9,99. O tempo mínimo de acompanhamento pós-operatório foi de 90 dias. Foram excluídos indivíduos com topografia corneana pré-operatória com ceratometria máxima maior que 46,5D ou presença de irregularidades; ceratometria média pós-operatória simulada menor que 36,0D; pupilas maiores que 6mm; paquimetria menor que 500 µm; miopia maior que -8,0DE, hipermetropia maior que +5,0DE e astigmatismo maior que -4,0DC. O laser utilizado foi o Esiris Schwind com Eye-Tracking de 350Hz e scanning spot de 0,8 mm. O microcerátomo utilizado foi o M2 da Moria com programação de 130µm de espessura. Resultados: A acuidade visual logMAR pré-operatória com correção variou de 0,40 a 0 com média de 0,23 ± 0,69; a pós-operatória sem correção foi de 0,40 a 0 com média de 0,30 ± 0,68. A mediana foi de 0 logMAR para os dois momentos (p=0,424). No equivalente esférico pré e pós-operatório, notou-se uma óbvia diferença (p< 0,0001), no pré-operatório com média de -4,09 ± 2,83 e o pós com média de -0,04 ± 0,38.
    [Show full text]
  • Laser Measurement in Medical Laser Service
    Laser Measurement in Medical Laser Service By Dan Little, Technical Director, Laser Training Institute, Professional Medical Education Association, Inc. The global medical industry incorporates thousands of lasers into its arsenal of treatment tools. Wavelengths from UV to Far-Infrared are used for everything from Lasik eye surgery to cosmetic skin resurfacing. Visible wavelengths are used in dermatology and ophthalmology to target selective complementary color chromophores. Laser powers and energies are delivered through a wide range of fiber diameters, articulated arms, focusing handpieces, scanners, micromanipulators, and more. With all these variables, medical laser service personnel are faced with multiple measurement obstacles. At the Laser Training Institute (http://www.lasertraining.org), with headquarters in Columbus Ohio, we offer a week-long laser service school to medical service personnel. Four times a year, a new class learns the fundamental concepts of power and energy densities, absorption, optics, and, most of all, how lasers work. With a nice sampling of all the major types of medical lasers, the students learn hands-on calibration, alignment, and multiple service skills. Lasers used in the medical field fall under stricter safety regulations than other laser usages. Meeting ANSI compliances are critical to the continued legal operation of all medical and aesthetic facilities. Laser output powers and energies are to be checked on a semi-annual basis according to FDA Regulations and are supported by ANSI recommendations which state regular scheduled intervals. In our service school we exclusively use Ophir-Spiricon laser measurement Instrumentation. We present a graphically enhanced presentation on measurement technologies and the many, varying, critical parameters that are faced with not only each different type of laser but design differences between manufacturers.
    [Show full text]
  • Laser Vision Correction: a Tutorial for Medical Students
    Laser Vision Correction: A Tutorial for Medical Students Written by: Reid Turner, M4 Reviewed by: Anna Kitzmann, MD Illustrations by: Steve McGaughey, M4 November 29, 2011 1. Introduction Laser vision correction is the world’s most popular elective surgery with roughly 700,000 LASIK procedures performed in the U.S. each year (AAO, 2008). Since refractive errors affect half of the U.S. population 20 years of age and older, it comes as no surprise that many people are turning to laser vision correction to obtain improved vision (Vitale et al. 2008). Due to its popularity, medical students will inevitably be asked by patients, family, and friends about refractive eye surgery. It is important to have a basic understanding of laser vision correction, outcomes, and associated risks. The goal of laser vision correction is to decrease dependence on glasses and contact lenses by focusing light more effectively on the retina. While there are a number of different surgeries used to achieve this result, this tutorial will focus specifically on laser vision correction, which consists of laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). In the U.S., LASIK comprises about 85% of the laser vision correction market with PRK making up the other 15% (ISRS 2009). The cost of surgery varies in price from hundreds to thousands of dollars and is not covered by insurance, similar to cosmetic surgery. Laser vision correction is regarded as highly effective with studies showing 94% of patients achieving uncorrected visual acuity of 20/40 or better at 12 months (Salz et al. 2002), which is the visual acuity needed to drive without corrective lenses in most states.
    [Show full text]
  • Ophthalmic Laser Therapy: Mechanisms and Applications
    1 Ophthalmic Laser Therapy: Mechanisms and Applications Daniel Palanker Department of Ophthalmology and Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA Definition The term LASER is an abbreviation which stands for Light Amplification by Stimulated Emission of Radiation. The laser is a source of coherent, directional, monochromatic light that can be precisely focused into a small spot. The laser is a very useful tool for a wide variety of clinical diagnostic and therapeutic procedures. Principles of Light Emission by Lasers Molecules are made up of atoms, which are composed of a positively charged nucleus and negatively charged electrons orbiting it at various energy levels. Light is composed of individual packets of energy, called photons. Electrons can jump from one orbit to another by either, absorbing energy and moving to a higher level (excited state), or emitting energy and transitioning to a lower level. Such transitions can be accompanied by absorption or spontaneous emission of a photon. “Stimulated Emission” is a process in which photon emission is stimulated by interaction of an atom in excited state with a passing photon. The photon emitted by the atom in this process will have the same phase, direction of propagation and wavelength as the “stimulating photon”. The “stimulating photon” does not lose energy during this interaction- it simply causes the emission and continues on, as illustrated in Figure 1. Figure 1: LASER: Light Amplification by Stimulated Emission of Radiation For such stimulated emission to occur more frequently than absorption (and hence result in light amplification), the optical material should have more atoms in excited state than in a lower state.
    [Show full text]
  • Slitlamp, Specular, and Light Microscopic Findings of Human Donor Corneas After Laser-Assisted in Situ Keratomileusis
    CLINICAL SCIENCES Slitlamp, Specular, and Light Microscopic Findings of Human Donor Corneas After Laser-assisted In Situ Keratomileusis V. Vinod Mootha, MD; Dan Dawson, MD; Amit Kumar, MD; Joel Gleiser, MD; Clifford Qualls, PhD; Daniel M. Albert, MD Objective: To examine slitlamp, specular, and light mi- slitlamp examination, of which 3 were confirmed by his- croscopic features of human donor corneas known to have topathologic examination. Highly reflective particles were undergone laser-assisted in situ keratomileusis (LASIK). seen by specular microscopy in the stroma of 23 (88%) of 26 LASIK donor corneas, but only 1 (4%) of 26 con- Methods: Twenty-six donor corneas known to have un- trol donor corneas had a single highly reflective particle dergone LASIK prospectively underwent slitlamp exami- in the stroma (PϽ.001). The mean central endothelial nation with particular attention to the presence of a flap cell counts were similar: 2138 cells/mm2 in the LASIK edge, as well as specular microscopy with particular at- group compared with 2250 cells/mm2 in the controls tention to the presence of highly reflective particles in (P=.39). Vacuolization and pyknosis of keratocytes the stroma corresponding to the LASIK interface. Cen- was a consistent histopathologic finding after LASIK. tral endothelial cell density and pachymetery were ob- Metallic particles at the interface were not detected by tained. They were compared with 26 control donor cor- histology. neas without LASIK. Eleven LASIK donor corneas were processed for histology. Twenty-six donor corneas with Conclusions: Detection of a flap edge by slitlamp ex- no known prior keratorefractive surgery also under- amination may detect at least half of the donor corneas went similar slitlamp examination and specular micros- that may have undergone LASIK.
    [Show full text]
  • Ifs® Advanced Femtosecond Laser Specifications for Site Preparation/Installation
    iFS® Advanced Femtosecond Laser Specifications For Site Preparation/Installation Recommended Room Requirements • Minimum requirement: 10 ft x 10 ft (3048 mm x 3048 mm) • Ambient temperature: 67° F to 73° F (19° C to 23° C) (stable 24 hours a day) • Humidity requirement: Relative humidity between 35% to 65% (non-condensing) • The line voltage should be tested upon installation to ensure proper operation and should not vary by more than ± 10 % from nominal • Line Condition Max Current 120 VAC, 60 Hz 7 A 100 VAC, 50 Hz to 60 Hz 10 A 220-240 VAC, 50 Hz to 60 Hz 4 A o Dedicated AC line required prior to system installation (Laser UPS on electrical line connected to one breaker at panel) • Independent thermostat, controlling laser room only, required prior to system installation • High-speed Internet connection with static IP address required prior to system installation Delivery system shown in the retracted position. INDICATION: The iFS® Laser is a precise ophthalmic surgical laser indicated for use in patients undergoing surgery or other treatment requiring initial lamellar resection of the cornea. System Specifications Hardware Components • Dimensions and Weight: o Height: 60 in (152 cm) o Width: 47 in (119 cm) o Length: 41 in (104 cm) o Weight: 865 lbs (392 kg) • Laser Type: Mode-locked, diode-pumped Nd: glass oscillator with a diode-pumped regenerative amplifier • Pulse Repetition Rate: 150 kHz • Laser Pulse Duration: 600 fs to 800 fs (±50 fs) • Maximum Laser Pulse Peak Power: 4.2 mW (±0.8 mW) • Central Laser Wavelength: 1053 nm • Remote
    [Show full text]
  • PRL™. Una Alternativa Al LASIK
    ARCH. SOC. CANAR. OFTAL., 2002; 13: 27-31 ARTÍCULO ORIGINAL PRL™. Una alternativa al LASIK PRL™. An alternative to LASIK AMIGÓ RODRÍGUEZ A1, HERRERA PIÑERO R2, MUIÑOS GÓMEZ-CAMACHO JA2 RESUMEN Objetivo: Estudiar los resultados iniciales de la Lente Fáquica Refractiva (PRL™) implantada en pacientes miopes no susceptibles de ser corregidos mediante LASIK. Material y Métodos: A pacientes con miopía, con o sin astigmatismo, en los que existían con- traindicaciones para el LASIK y que cumplían con los criterios de inclusión, se les ofreció como alternativa la PRL™. Se analiza la dificultad técnica y las complicaciones per y pos- toperatorias así como los resultados visuales al mes evaluando el defecto refractivo previo, la exactitud en el cálculo de la potencia de la PRL™, la mejor agudeza visual (MAV) pre- operatoria, la AV obtenida sin corrección y la MAV postoperatoria. Resultados: Se implantó una PRL™ en 12 ojos de 7 pacientes. La dificultad técnica fue baja y no se presentaron otras complicaciones que edema corneal en 2 casos e iritis leve en otros 2 que cedieron en la primera semana. El defecto refractivo previo medio fue de –13,00 D (–9,50 / –16,00), el defecto refractivo postoperatorio medio fue –0,06 ± 0,6D (–1,25 / 0,87), la MAV preoperatoria se mantuvo en 1 caso, mejoró 1 línea en 5, 2 líneas en 4, 3 o más líneas en otros 2 casos. En ningún caso hubo pérdida de MAV preoperatoria. Conclusiones: Los resultados iniciales con la PRL™ nos revelan que es técnicamente sencilla de implantar y muy bien tolerada. El cálculo de potencia es muy bueno y los resultados visuales sobresalientes, mejorando en el 84% de los casos la mejor agudeza visual preope- ratoria.
    [Show full text]
  • Patient Guide to Excimer Laser Refractive Surgery
    A Patients’ Guide to Excimer Laser Refractive Surgery July 2011 Contents 1. Introduction 2. Understanding your refractive error 3. Changing the eye’s focus by surgery (refractive surgery) 4. Indications and contraindications to refractive surgery 5. Assessment for excimer laser refractive surgery 6. The day of surgery 7. The period after surgery 8. Results 9. Complications 10. Standards for laser refractive surgery 11. Glossary Royal College of Ophthalmologists 2 1. Introduction Focusing (refractive) errors such as short-sightedness (myopia), astigmatism, and long-sightedness (hyperopia) are usually corrected by wearing spectacles or contact lenses. Over the years a number of surgical techniques have been used to treat refractive errors and reduce the need for glasses (Table 1.1). The most common treatment uses an excimer laser. The following information explains the different excimer techniques, their advantages and disadvantages and the various terms used. Its aim is to help you come to an informed decision about any prospective treatment. If you have any further questions, your ophthalmic surgeon who will be performing the treatment should answer them. There are other surgical techniques as well as using the excimer laser. These other techniques are summarised in Table 1. Some are much more commonly used than others. (Please see section 2 for an explanation of the focusing problems of the eye). Site of Treatment Technique Procedure Indications Corneal techniques Excimer laser PRK – Photo- Low, mod & high: Refractive myopia Keratectomy
    [Show full text]
  • Permaclear® Sight Restoration Delivers
    Volume 3, Issue 4 Winter 2009 Exclusive New An sletter from the Al exand Avery D. Alexander, MD er Ey e Ins Refractive Surgery Specialist & ® titu Medical Director – Alexander Eye PermaClear Sight Restoration te Institute Delivers Clear Vision To Last A Lifetime. Dr. Alexander is a national leader and pioneer in laser vision correction and Baby Boomers ... and more ... benefit from this sight restoration techniques. He was among the first eye surgeons in the advanced procedure. nation to perform LASIK, serving as a hile millions of Dr. Alexander fine-tunes the patient’s vision using core investigator for the VISX eximer WAmericans now enjoy the Allegretto Wave™ Eye-Q laser, the same state- laser, one of the earliest medical lasers clear vision without glasses of-the-art technology used for UltraSight® LASIK. used for vision correction. Dr. Alexander By combining these two highly effective and was the first physician in Wisconsin to or contacts thanks to the use the state-of-the-art Allegretto Wave® advanced laser technology of proven approaches to vision correction, Dr. laser – the fastest and most accurate laser LASIK, millions more are Alexander is able to help patients achieve a level of system available for vision correction. not candidates for this life- visual acuity at all distances that is unsurpassed. changing procedure. The “The multi-focal lens we use – Acrysof® ReSTOR® • Board Certification reason? Usually it’s because their vision problem – – is unique,” said Dr. Alexander. “It enables a American Academy of Ophthalmology whether they are nearsighted, farsighted or have majority of patients not only to see clearly at a • Undergraduate Degree astigmatism – is complicated by presbyopia, the distance but to perform near- and mid-range tasks University of Virginia aging of the eye’s natural lenses.
    [Show full text]
  • A Patient's Experience at Two LASIK Chains
    COVER STORY A Patient’s Experience at Two LASIK Chains National LASIK centers are formidable competition to the independent surgeon. In this article, a prospective patient offers a glimpse of her experience at LasikPlus and TLC. BY LEAH FARR, NEWS AND INDUSTRY EDITOR n my experience, finding a LASIK surgeon was a lot first step toward perfect vision.” The surgery cost like buying a car: it combined a little excitement, a between $1,800 and $3,100 per eye, she said, and bit of confusion, a fast-talking salesman, and some financing was available. Additionally, the surgeons were not-so-subtle pushes toward the shiny and new “some of the most experienced in the region, having Iautomatic version versus the older, manual model. performed more than 18,000 surgeries combined.” Did I want extra safety features for an additional Several days later, I showed up for my first consulta- $350? What about a lifetime warranty? I desperately tion with a slight sense of nervousness. As I walked into wanted to trade in my eyes, but, with so many options, a typical-looking waiting room, I recalled stories from I felt that it was in my best interest to shop around. doctors who turned their waiting rooms into some- I have worn eyeglasses for most of my life, but, until thing resembling a high-end hotel lobby to help project this point, I had not given LASIK much consideration. In the value of their product. The idea is that people want fact, before these consultations, I was not even sure if I elective medical procedures to feel like a trip to the spa.
    [Show full text]