DOCSLIB.ORG

Large Proteoglycan Complexes and Disturbed Collagen Architecture in the Corneal Extracellular Matrix of Mucopolysaccharidosis Type VII (Sly Syndrome)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Large Proteoglycan Complexes and Disturbed Collagen Architecture in the Corneal Extracellular Matrix of Mucopolysaccharidosis Type VII (Sly Syndrome) Cornea Large Proteoglycan Complexes and Disturbed Collagen Architecture in the Corneal Extracellular Matrix of Mucopolysaccharidosis Type VII (Sly Syndrome) Robert D. Young,1 Petra Liskova,2 Christian Pinali,1 Barbara P. Palka,1 Michalis Palos,3 Katerina Jirsova,2 Enkela Hrdlickova,3 Marketa Tesarova,4 Milan Elleder,5 Jiri Zeman,4 Keith M. Meek,1 Carlo Knupp,1 and Andrew J. Quantock1 PURPOSE. Deficiencies in enzymes involved in proteoglycan CONCLUSIONS. Cellular changes in the MPS VII cornea resemble (PG) turnover underlie a number of rare mucopolysacchari- those in other MPS. However, the wide range of collagen fibril doses (MPS), investigations of which can considerably aid un- diameters throughout the stroma and the extensive matrix derstanding of the roles of PGs in corneal matrix biology. Here, presence of supranormal-sized PG structures appear to be the authors analyze novel pathologic changes in MPS VII (Sly unique features of this disorder. The findings suggest that the syndrome) to determine the nature of PG-collagen associations accumulation of stromal chondroitin-, dermatan-, and heparan- ␤ in stromal ultrastructure. sulfate glycosaminoglycans in the absence of -glucuronidase- mediated degradation can modulate collagen fibrillogenesis. (In- METHODS. Transmission electron microscopy and electron to- vest Ophthalmol Vis Sci. 2011;52:6720–6728) DOI:10.1167/ mography were used to investigate PG-collagen architectures iovs.11-7377 and interactions in a cornea obtained at keratoplasty from a 22-year-old man with MPS VII, which was caused by a com- he mucopolysaccharidoses (MPS) are a group of lysosomal pound heterozygous mutation in the GUSB gene. Tstorage diseases caused by inherited defects in specific ESULTS enzymes involved in the degradation of glycosaminoglycans R . Transmission electron microscopy showed atypical 1–3 morphology of the epithelial basement membrane and Bow- (GAGs). The result is a widespread accumulation of derma- man’s layer in MPS VII. Keratocytes were packed with cyto- tan sulfate (DS), chondroitin sulfate (CS), heparan sulfate (HS), or keratan sulfate (KS) in the majority of organs and tissues and plasmic vacuoles containing abnormal glycosaminoglycan a wide range of clinical manifestations. Ocular involvement (GAG) material, and collagen fibrils were thinner than in nor- attributed to GAG deposition in MPS includes progressive cor- mal cornea and varied considerably throughout anterior neal clouding, glaucoma, retinal degeneration, and optic disc (14–32 nm), mid (13–42 nm), and posterior (17–39 nm) re- swelling followed by its atrophy.4 In a mouse model of MPS gions of the MPS VII stroma. PGs viewed in three dimensions VII, progressive photoreceptor death has also been observed.5 were striking in appearance in that they were significantly The cornea is affected in all the MPS subtypes classified to date, larger than PGs in normal cornea and formed highly extended with a significant overlap of corneal phenotype between, and linkages with multiple collagen fibrils. also within, the MPS types and a variety of treatment op- tions.6,7 MPS VII (Sly syndrome; Mendelian Inheritance in Man (MIM) #253220) is a rare, autosomal recessive, inherited con- From the 1Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom; dition with an estimated incidence of 1 in 250,000 births, the 2Ocular Tissue Bank and Laboratory of the Biology and Pathology which is one of the lowest of all MPS. Accumulation of unde- of the Eye, Institute of Inherited Metabolic Disorders, the Departments graded GAGs typically leads to short stature, bone dysplasia, of 3Ophthalmology and 4Pediatrics and Adolescent Medicine, and the hepatosplenomegaly, hydrops fetalis, and mental retarda- 5Institute of Inherited Metabolic Disorders, First Faculty of Medicine, tion.8,9 The course of the disease is considered clinically atten- Charles University in Prague and General University Hospital in Prague, uated if there is no hydrops fetalis or severe mental retardation Prague, Czech Republic. and if the condition does not lead to death within a year.8 Most Supported by Biotechnology and Biological Sciences Research children with MPS VII live into teenage or young adult years. Council UK Project Grant BB/F022077/1 (CK, AJQ), Engineering and Various approaches toward therapy have been investigated Physical Sciences Research Council UK Research Grant EP/F034970/1 in mutant MPS VII mice, including bone marrow transplanta- (AJQ, KMM, RDY), and Medical Research Council UK Programme 10 11 Grant G0600755 (KMM, AJQ), the Research Project of the Ministry of tion, enzyme replacement therapy, transplacental delivery 12 Education, Youth and Sports of the Czech Republic Grant of the deficient enzyme tagged to Fc into the fetal circulation, MSM0021620806 (PL, KJ, ME), and the Research Project of the Ministry gene therapy,13,14 encapsulation,15 and stem cell therapy.16 of Health of the Czech Republic Grant MZOVFN2005 (JZ, MT). However, no effective treatment is yet available for affected Submitted for publication February 11, 2011; revised June 9, 2011; human patients. MPS VII is caused by deficiencies of ␤-glucu- accepted June 28, 2011. ronidase enzyme (GUSB), leading to an accumulation of DS, Disclosure: R.D. Young, None; P. Liskova, None; C. Pinali, None; HS, and CS GAGs in the cells and tissues.17 Forty-nine unique B.P. Palka, None; M. Palos, None; K. Jirsova, None; E. Hrdlickova, disease-causing mutations in the ␤-glucuronidase gene (GUSB None; M. Tesarova, None; M. Elleder, None; J. Zeman, None; K.M. Meek, None; C. Knupp, None; A.J. Quantock, None MIM #611499) have been identified in persons with MPS VII Corresponding author: Andrew J. Quantock, Structural Biophysics from various populations. Heterogeneity of pathogenic Group, School of Optometry and Vision Sciences, Cardiff University, changes, with different effects on the function of the mutant Maindy Road, Cardiff CF24 4LU, Wales, United Kingdom; proteins, manifests as extensive clinical variability among pa- [email protected]. tients with MPS VII.18 Investigative Ophthalmology & Visual Science, August 2011, Vol. 52, No. 9 6720 Copyright 2011 The Association for Research in Vision and Ophthalmology, Inc. Downloaded from iovs.arvojournals.org on 09/26/2021 IOVS, August 2011, Vol. 52, No. 9 Proteoglycans in Mucopolysaccharidosis Type VII 6721 Proteoglycans (PGs) with their GAG side chains, in partic- suggesting MPS diagnosis were present at birth. The ␤-glucuronidase ular those of the small leucine-rich PG family of molecules, are activity in isolated leukocytes was Ͻ2% of controls. Molecular genetic implicated in the regulation of fibrillar order in cornea. Recent analysis of the GUSB gene revealed compound heterozygosity for two studies on corneal three-dimensional structure using electron missense mutations, c.[155CϾT] ϩ [1120CϾT], leading to amino acid tomography have provided new insights into how PGs may changes p.Ser52Phe and p.Arg374Cys.22 Medical examination at the help to maintain the ordered architecture of the stroma essen- age of 24 years revealed short stature (155 cm), a body weight of 65 kg, tial for tissue transparency.19–21 Here, we describe a case of and head circumference 61 cm, plus retroflexion of the head with a MPS VII in which grafting was carried out to treat a reduction short neck, sternal prominence, lumbar hyperlordosis, and hepato- of corneal transparency. Clinical, biochemical, molecular ge- splenomegaly. An x-ray survey showed typical signs of dysostosis netic, histologic, and ultrastructural examinations of explanted multiplex. There were thickened aortic and mitral valves on echocar- MPS VII corneal tissue were performed, with comparisons with diography and an obstructive type of ventilation with a forced vital data obtained from a healthy human donor cornea acquired capacity of 74%. The urinary GAG excretion, measured on several from an eye bank. Data indicate that disturbance in PG turn- occasions, was increased between 8 and 25 g/mol creatinine compared over resulting from a GUSB deficiency leads to alterations in with a normal value in adults of 1.8 Ϯ 0.6 g/mol,23 with higher both fibrillar and interfibrillar components of the corneal fractions of CS and DS. The patient was not mentally retarded and was stroma. able to read, and several IQ tests performed since childhood revealed scores of 81 to 85. MATERIALS AND METHODS At 5 years of age, the patient’s best-corrected visual acuity (BCVA) was 0.4 in both eyes and mild corneal clouding was noticed. Refraction The study conformed to the tenets of the Helsinki Declaration and local was ϩ4.0/Ϫ5.0 D ϫ 7° in the right eye and ϩ3.0/Ϫ4.5 D ϫ 174° in the ethics codes. left. At 14 years of age, the patient was referred to the Department of Ophthalmology in Prague with BCVAs of 0.33 (right eye) and 0.4 (left Medical and Ocular History eye). Because of progressive corneal clouding, a penetrating kerato- The patient reported here was a male, an only child, born to healthy, plasty (8-mm diameter button) was performed in the right eye at the unrelated parents after an unremarkable pregnancy. Clinical features age of 20 years and in the left eye at the age of 22 years. Before surgery, FIGURE 1. Ocular findings in a pa- tient with mucopolysaccharidosis VII. (A, B) Diffuse fine cloudiness in corneal stroma of the right eye be- fore surgery. (C) Videotopography reveals regular astigmatism in the left eye before grafting. (D) Six months after keratoplasty in the right eye. (E) Normal postoperative appearance of fundus in the right eye. (F) Normal appearance of the macular region on OCT in the right eye. Downloaded from iovs.arvojournals.org on 09/26/2021 6722 Young et al. IOVS, August 2011, Vol. 52, No. 9 diffuse opacification involving all corneal layers was observed bilater- were fixed for 20 hours at room temperature with 2.5% glutaraldehyde ally (Fig. 1), with a BCVA of 0.33 in the right eye and 0.11 in the left.
Load more

Recommended publications
  • 12 Retina Gabriele K
    299 12 Retina Gabriele K. Lang and Gerhard K. Lang 12.1 Basic Knowledge The retina is the innermost of three successive layers of the globe. It comprises two parts: ❖ A photoreceptive part (pars optica retinae), comprising the first nine of the 10 layers listed below. ❖ A nonreceptive part (pars caeca retinae) forming the epithelium of the cil- iary body and iris. The pars optica retinae merges with the pars ceca retinae at the ora serrata. Embryology: The retina develops from a diverticulum of the forebrain (proen- cephalon). Optic vesicles develop which then invaginate to form a double- walled bowl, the optic cup. The outer wall becomes the pigment epithelium, and the inner wall later differentiates into the nine layers of the retina. The retina remains linked to the forebrain throughout life through a structure known as the retinohypothalamic tract. Thickness of the retina (Fig. 12.1) Layers of the retina: Moving inward along the path of incident light, the individual layers of the retina are as follows (Fig. 12.2): 1. Inner limiting membrane (glial cell fibers separating the retina from the vitreous body). 2. Layer of optic nerve fibers (axons of the third neuron). 3. Layer of ganglion cells (cell nuclei of the multipolar ganglion cells of the third neuron; “data acquisition system”). 4. Inner plexiform layer (synapses between the axons of the second neuron and dendrites of the third neuron). 5. Inner nuclear layer (cell nuclei of the bipolar nerve cells of the second neuron, horizontal cells, and amacrine cells). 6. Outer plexiform layer (synapses between the axons of the first neuron and dendrites of the second neuron).
    [Show full text]
  • Morphological Aspect of Tapetum Lucidum at Some Domestic Animals
    Bulletin UASVM, Veterinary Medicine 65(2)/2008 pISSN 1843-5270; eISSN 1843-5378 MORPHOLOGICAL ASPECT OF TAPETUM LUCIDUM AT SOME DOMESTIC ANIMALS Donis ă Alina, A. Muste, F.Beteg, Roxana Briciu University of Angronomical Sciences and Veterinary Medicine Calea M ănăş tur 3-5 Cluj-Napoca [email protected] Keywords: animal ophthalmology, eye fundus, tapetum lucidum. Abstract: The ocular microanatomy of a nocturnal and a diurnal eye are very different, with compromises needed in the arrhythmic eye. Anatomic differences in light gathering are found in the organization of the retina and the optical system. The presence of a tapetum lucidum influences the light. The tapetum lucidum represents a remarkable example of neural cell and tissue specialization as an adaptation to a dim light environment and, despite these differences, all tapetal variants act to increase retinal sensitivity by reflecting light back through the photoreceptor layer. This study propose an eye fundus examination, in animals of different species: cattles, sheep, pigs, dogs cats and rabbits, to determine the presence or absence of tapetum lucidum, and his characteristics by species to species, age and even breed. Our observation were made between 2005 - 2007 at the surgery pathology clinic from FMV Cluj, on 31 subjects from different species like horses, dogs and cats (25 animals). MATERIAL AND METHOD Our observation were made between 2005 - 2007 at the surgery pathology clinic from FMV Cluj, on 30 subjects from different species like cattles, sheep, pigs, dogs cats and rabbits.The animals were halt and the examination was made with minimal tranquilization. For the purpose we used indirect ophthalmoscopy method with indirect ophthalmoscope Heine Omega 2C.
    [Show full text]
  • Optic Disc Edema, Globe Flattening, Choroidal Folds, and Hyperopic Shifts Observed in Astronauts After Long-Duration Space Flight
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln NASA Publications National Aeronautics and Space Administration 10-2011 Optic Disc Edema, Globe Flattening, Choroidal Folds, and Hyperopic Shifts Observed in Astronauts after Long-duration Space Flight Thomas H. Mader Alaska Native Medical Center, [email protected] C. Robert Gibson Coastal Eye Associates Anastas F. Pass University of Houston Larry A. Kramer University of Texas Health Science Center Andrew G. Lee The Methodist Hospital See next page for additional authors Follow this and additional works at: https://digitalcommons.unl.edu/nasapub Part of the Physical Sciences and Mathematics Commons Mader, Thomas H.; Gibson, C. Robert; Pass, Anastas F.; Kramer, Larry A.; Lee, Andrew G.; Fogarty, Jennifer; Tarver, William J.; Dervay, Joseph P.; Hamilton, Douglas R.; Sargsyan, Ashot; Phillips, John L.; Tran, Duc; Lipsky, William; Choi, Jung; Stern, Claudia; Kuyumjian, Raffi; andolk, P James D., "Optic Disc Edema, Globe Flattening, Choroidal Folds, and Hyperopic Shifts Observed in Astronauts after Long-duration Space Flight" (2011). NASA Publications. 69. https://digitalcommons.unl.edu/nasapub/69 This Article is brought to you for free and open access by the National Aeronautics and Space Administration at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in NASA Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Thomas H. Mader, C. Robert Gibson, Anastas F. Pass, Larry A.
    [Show full text]
  • Characteristics of Structures and Lesions of the Eye in Laboratory Animals Used in Toxicity Studies
    J Toxicol Pathol 2015; 28: 181–188 Concise Review Characteristics of structures and lesions of the eye in laboratory animals used in toxicity studies Kazumoto Shibuya1*, Masayuki Tomohiro2, Shoji Sasaki3, and Seiji Otake4 1 Testing Department, Nippon Institute for Biological Science, 9-2221-1 Shin-machi, Ome, Tokyo 198-0024, Japan 2 Clinical & Regulatory Affairs, Alcon Japan Ltd., Toranomon Hills Mori Tower, 1-23-1 Toranomon, Minato-ku, Tokyo 105-6333, Japan 3 Japan Development, AbbVie GK, 3-5-27 Mita, Minato-ku, Tokyo 108-6302, Japan 4 Safety Assessment Department, LSI Medience Corporation, 14-1 Sunayama, Kamisu-shi, Ibaraki 314-0255, Japan Abstract: Histopathology of the eye is an essential part of ocular toxicity evaluation. There are structural variations of the eye among several laboratory animals commonly used in toxicity studies, and many cases of ocular lesions in these animals are related to anatomi- cal and physiological characteristics of the eye. Since albino rats have no melanin in the eye, findings of the fundus can be observed clearly by ophthalmoscopy. Retinal atrophy is observed as a hyper-reflective lesion in the fundus and is usually observed as degenera- tion of the retina in histopathology. Albino rats are sensitive to light, and light-induced retinal degeneration is commonly observed because there is no melanin in the eye. Therefore, it is important to differentiate the causes of retinal degeneration because the lesion occurs spontaneously and is induced by several drugs or by lighting. In dogs, the tapetum lucidum, a multilayered reflective tissue of the choroid, is one of unique structures of the eye.
    [Show full text]
  • Ophthalmology Abbreviations Alphabetical
    COMMON OPHTHALMOLOGY ABBREVIATIONS Listed as one of America’s Illinois Eye and Ear Infi rmary Best Hospitals for Ophthalmology UIC Department of Ophthalmology & Visual Sciences by U.S.News & World Report Commonly Used Ophthalmology Abbreviations Alphabetical A POCKET GUIDE FOR RESIDENTS Compiled by: Bryan Kim, MD COMMON OPHTHALMOLOGY ABBREVIATIONS A/C or AC anterior chamber Anterior chamber Dilators (red top); A1% atropine 1% education The Department of Ophthalmology accepts six residents Drops/Meds to its program each year, making it one of nation’s largest programs. We are anterior cortical changes/ ACC Lens: Diagnoses/findings also one of the most competitive with well over 600 applicants annually, of cataract whom 84 are granted interviews. Our selection standards are among the Glaucoma: Diagnoses/ highest. Our incoming residents graduated from prestigious medical schools ACG angle closure glaucoma including Brown, Northwestern, MIT, Cornell, University of Michigan, and findings University of Southern California. GPA’s are typically 4.0 and board scores anterior chamber intraocular ACIOL Lens are rarely lower than the 95th percentile. Most applicants have research lens experience. In recent years our residents have gone on to prestigious fellowships at UC Davis, University of Chicago, Northwestern, University amount of plus reading of Iowa, Oregon Health Sciences University, Bascom Palmer, Duke, UCSF, Add power (for bifocal/progres- Refraction Emory, Wilmer Eye Institute, and UCLA. Our tradition of excellence in sives) ophthalmologic education is reflected in the leadership positions held by anterior ischemic optic Nerve/Neuro: Diagno- AION our alumni, who serve as chairs of ophthalmology departments, the dean neuropathy ses/findings of a leading medical school, and the director of the National Eye Institute.
    [Show full text]
  • Entoptic Phenomena and Reproducibility Ofcorneal Striae
    Br J Ophthalmol: first published as 10.1136/bjo.71.10.737 on 1 October 1987. Downloaded from British Journal of Ophthalmology, 1987, 71, 737-741 Entoptic phenomena and reproducibility of corneal striae following contact lens wear MURRAY H JOHNSON, C MONTAGUE RUBEN, AND DAVID M PERRIGIN From the Institutefor Contact Lens Research, University of Houston- University Park, 4901 Calhoun Road, Houston, Texas 77004, USA SUMMARY Vertical corneal striae distributed across the posterior cornea are one of the objective signs ofclinically unacceptable corneal swelling (>6%) resulting from contact lens wear. This study reports that corneal striae are repeatable both in configuration and location with different levels of hypoxia. In most instances entoptic phenomena result from the presence of these lines. The results suggest that the healthy, avascular, transparent cornea has certain localised areas in its anatomical structure which may give rise to bundles of collagen fibres being made visible objectively and subjectively during conditions of corneal swelling. Corneal striae is a term used to describe lines seen in vidual was strikingly similar. Furthermore, there was the corneal stroma of varied appearance, aetiology, intrasubject repeatability of striae with large inter- and pathology. Deep striae have been seen as a result subject variability of corneal striate lines. of trauma (penetrating wounds),' after intraocular In this paper we describe the repeatability and operations (striate keratitis),' in degenerative entoptic phenomena of corneal
    [Show full text]
  • Retinal Pigment Epithelial Lipofuscin and Melanin and Choroidal Melanin in Human Eyes
    Retinal Pigment Epithelial Lipofuscin and Melanin and Choroidal Melanin in Human Eyes John J. Weirer,*t Francois C. Delori,*t Glenn L. Wing,t and Karbrra A. Fitch* Optical measurements of the pigments of the retinal pigment epithelium (RPE) and choroid were made on 38 human autopsy eyes of both blacks and whites, varying in age between 2 wk and 90 yr old. Lipofuscin in melanin-bleached RPE was measured as fluorescence at 470 mm following excitation at 365 nm and was found to be proportional to fluorescence measured at 560 nm in unbleached tissue. Transmission measurements of RPE and choroidal melanin were converted and expressed as optical density units. The choroidal melanin content increased from the periphery to the posterior pole. RPE melanin concentration decreased from the periphery to the posterior pole with an increase in the macula. Conversely, the amount of RPE lipofuscin increased from the periphery to the posterior pole with a consistent dip at the fovea. There was an inverse relationship between RPE lipofuscin concentration and RPE melanin concentration. The RPE melanin content was similar between whites and blacks. Lipofuscin concentration was significantly greater (P = 0.002) in the RPE of whites compared to blacks; whereas blacks had a significantly greater (P = 0.005) choroidal melanin content than whites. The amounts of both choroidal and RPE melanin showed a trend of decreasing content with aging, whereas the amount RPE lipofuscin tended to increase (whites > blacks). Per fundus area, the amount of choroidal melanin was always greater than that in the RPE. There was a statistically significant (P = 0.001) increase in RPE height with age, most marked in eyes of whites after age 50 and correlated with the increase in lipofuscin concentration.
    [Show full text]
  • 98796-Anatomy of the Orbit
    Anatomy of the orbit Prof. Pia C Sundgren MD, PhD Department of Diagnostic Radiology, Clinical Sciences, Lund University, Sweden Lund University / Faculty of Medicine / Inst. Clinical Sciences / Radiology / ECNR Dubrovnik / Oct 2018 Lund University / Faculty of Medicine / Inst. Clinical Sciences / Radiology / ECNR Dubrovnik / Oct 2018 Lay-out • brief overview of the basic anatomy of the orbit and its structures • the orbit is a complicated structure due to its embryological composition • high number of entities, and diseases due to its composition of ectoderm, surface ectoderm and mesoderm Recommend you to read for more details Lund University / Faculty of Medicine / Inst. Clinical Sciences / Radiology / ECNR Dubrovnik / Oct 2018 Lund University / Faculty of Medicine / Inst. Clinical Sciences / Radiology / ECNR Dubrovnik / Oct 2018 3 x 3 Imaging technique 3 layers: - neuroectoderm (retina, iris, optic nerve) - surface ectoderm (lens) • CT and / or MR - mesoderm (vascular structures, sclera, choroid) •IOM plane 3 spaces: - pre-septal •thin slices extraconal - post-septal • axial and coronal projections intraconal • CT: soft tissue and bone windows 3 motor nerves: - occulomotor (III) • MR: T1 pre and post, T2, STIR, fat suppression, DWI (?) - trochlear (IV) - abducens (VI) Lund University / Faculty of Medicine / Inst. Clinical Sciences / Radiology / ECNR Dubrovnik / Oct 2018 Lund University / Faculty of Medicine / Inst. Clinical Sciences / Radiology / ECNR Dubrovnik / Oct 2018 Superior orbital fissure • cranial nerves (CN) III, IV, and VI • lacrimal nerve • frontal nerve • nasociliary nerve • orbital branch of middle meningeal artery • recurrent branch of lacrimal artery • superior orbital vein • superior ophthalmic vein Lund University / Faculty of Medicine / Inst. Clinical Sciences / Radiology / ECNR Dubrovnik / Oct 2018 Lund University / Faculty of Medicine / Inst.
    [Show full text]
  • Eye60. Instrumental Eye Examination.Pdf
    INSTRUMENTAL EYE EXAMINATION Eye60 (1) Instrumental Eye Examination Last updated: May 9, 2019 “BEDSIDE” EXAMINATIONS ..................................................................................................................... 1 OPHTHALMOSCOPY (FUNDUSCOPY) ........................................................................................................ 1 DIRECT OPHTHALMOSCOPY .................................................................................................................... 1 INDIRECT OPHTHALMOSCOPY ................................................................................................................. 2 OPHTHALMOSCOPIC FINDINGS ............................................................................................................... 2 Hypertensive retinopathy ................................................................................................................. 6 Diabetic retinopathy ......................................................................................................................... 7 PEDIATRIC ASPECTS ............................................................................................................................... 9 APPLANATION TONOMETRY .................................................................................................................... 9 SLIT LAMP EXAMINATION (BIOMICROSCOPY) ........................................................................................ 9 ULTRASONOGRAPHY ..............................................................................................................................
    [Show full text]
  • Anatomy and Physiology of the Afferent Visual System
    Handbook of Clinical Neurology, Vol. 102 (3rd series) Neuro-ophthalmology C. Kennard and R.J. Leigh, Editors # 2011 Elsevier B.V. All rights reserved Chapter 1 Anatomy and physiology of the afferent visual system SASHANK PRASAD 1* AND STEVEN L. GALETTA 2 1Division of Neuro-ophthalmology, Department of Neurology, Brigham and Womens Hospital, Harvard Medical School, Boston, MA, USA 2Neuro-ophthalmology Division, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA INTRODUCTION light without distortion (Maurice, 1970). The tear–air interface and cornea contribute more to the focusing Visual processing poses an enormous computational of light than the lens does; unlike the lens, however, the challenge for the brain, which has evolved highly focusing power of the cornea is fixed. The ciliary mus- organized and efficient neural systems to meet these cles dynamically adjust the shape of the lens in order demands. In primates, approximately 55% of the cortex to focus light optimally from varying distances upon is specialized for visual processing (compared to 3% for the retina (accommodation). The total amount of light auditory processing and 11% for somatosensory pro- reaching the retina is controlled by regulation of the cessing) (Felleman and Van Essen, 1991). Over the past pupil aperture. Ultimately, the visual image becomes several decades there has been an explosion in scientific projected upside-down and backwards on to the retina understanding of these complex pathways and net- (Fishman, 1973). works. Detailed knowledge of the anatomy of the visual The majority of the blood supply to structures of the system, in combination with skilled examination, allows eye arrives via the ophthalmic artery, which is the first precise localization of neuropathological processes.
    [Show full text]
  • Microsporidial Stromal Keratitis
    CLINICOPATHOLOGIC REPORTS, CASE REPORTS, AND SMALL CASE SERIES SECTION EDITOR: W. RICHARD GREEN, MD Microsporidial Stromal Keratitis Microsporida are spore-forming, ob- ligate eukaryotic protozoan para- sites that belong to the phylum Microspora. The ophthalmic mani- festations of ocular microsporidi- osis exhibit characteristic clinical fea- tures depending on the genus involved. With the genus Encepha- Figure 1. The clinical appearance of the right Figure 2. The clinical appearance of the right litozoon, infection is limited to the cornea at the time of the initial examination cornea 9 months after the initial examination epithelial cells of the cornea and con- shows a central area of stromal infiltration and displays a central epithelial defect associated junctiva, producing a diffuse punc- edema without suppuration. A 3% hypopyon is with a disciform opacity. Superficial peripheral tate epithelial keratoconjunctivitis. present inferiorly. corneal vascularization is observed superiorly. With the genera Nosema and Micro- sporidium, the infection typically in- and scrapings collected for bacte- wrinkled and folded. The endothe- volves the corneal stroma, includ- rial, chlamydial, fungal, and herpes- lium was attenuated with a retro- ing the keratocytes.1 virus cultures were all negative for corneal fibrovascular membrane, To date, only 5 case reports of microorganisms. containing few neutrophils. The cor- microsporidial stromal keratitis have Over the next 2 months, the vi- neal stroma showed round to oval been published.2-6 We report an ad- sual acuity improved to 20/25 OD, organisms measuring 2.0 to 4.0 µm. ditional case caused by Vittaforma with gradual resolution of the stro- These organisms were mostly lo- corneae (formerly known as No- mal edema.
    [Show full text]
  • Funduscopic Interpretation Understanding the Fundus: Is That Normal?
    Funduscopic Interpretation Understanding the Fundus: is that normal? Gillian McLellan BVMS PhD DVOphthal DECVO DACVO MRCVS With thanks to Christine Heinrich and all who contributed images Fundus ≠ Retina working knowledge of fundus anatomy how to evaluate the fundus systematically normal fundus variants hallmarks of fundus pathology Fundus anatomy Vitreous normally optically clear (almost) Only retinal vessels / pigmented RPE +/- inner choroid (tapetum) make a major contribution to the typical appearance of a normal fundus Retinal Vascular Patterns holangiotic Retinal Vascular Patterns Merangiotic Paurangiotic Anangiotic Retinal anatomy light traverses 8 retinal layers to reach photoreceptor O.S. photoreceptors largely responsible for translucent appearance of NSR cone density highest in area centralis or macula RPE = single cell layer Pigmented /non-tapetal Tapetal / non-pigmented retinal anatomy tapetum structure within the choroid cellular in dog and cat regular compacted collagen array in ruminants, horses visible due to absence of pigment in overlying RPE seen ophthalmoscopically as a bright, shiny sweep of color (or not) Tapetal fundus Non-Tapetal fundus RPE Tapetal development RPE completely pigments during fetal development Autophagy of melanin occurs in presumptive tapetal zone RPE depigments Tapetal maturation is not complete until 12-14 weeks of age in dogs and cats Connecting capillaries In areas of thin tapetum choroidal vessels may segmentally shine through, in some cases the long posterior ciliary artery, or vortex veins may also be seen Tapetal variation in equine fundus Feline tapetum – transient variant Normal : Non-tapetal fundus Varies in color depending on amount of melanin in RPE and choroid RPE contains melanin, tapetum absent Normal : Non-tapetal fundus • non-tapetal fundus • (optic disc) • (retinal blood vessels) RPE contains melanin, where the tapetum is absent.
    [Show full text]