1/9. fuchs' endothelial dystrophy: a fresh look at an aging disease.The increasing number or corneal and intraocular surgeries performed together with longer life expectancy, elevates the risk for developing symptomatic Fuchs' endothelial dystrophy (FED). This article reviews the current understanding of FED, and, in addition, a case of early FED is presented clinically and histopathologically. Two FED corneas from one patient were examined histopathologically using an established histological protocol for light and electron microscopy. FED is an inherited autosomal dominant corneal endothelial disorder with incomplete penetrance that is up to 3 times less likely to develop in men. Treatment options are primarily palliative while surgical intervention routinely involves a penetrating keratoplasty. In this disease process the endothelium produces excessive amounts of basement membrane material of an abnormal composition resulting in the formation of a posterior collagenous layer. Extreme accumulations of this material created mushroom-like formations, guttae, projecting into the anterior chamber. The endothelial cells were extremely thinned over the guttae, to the point where the cells may provide little more than barrier function. Despite a presumably compromised endothelial pump the corneas appeared relatively free of edema clinically and histopathologically. However, some edematous pockets deep in the basal epithelial layer were present suggesting that epithelial involvement occurs at an early stage in the disease. An early diagnosis of FED will help patients and surgeons to better elect optimal surgical timing and procedures. The current trend is to intervene surgically before the patient reaches the painful end-stage. Interestingly, in the case examined, the endothelium presumably provided only a barrier function over large areas with an apparently reduced contribution from the endothelial fluid pump and yet the corneas remained relatively clear. Future research may confirm that decompensation occurs only when complete endothelial coverage is lost. If the endothelial barrier function is more important to corneal transparency than the endothelial pump function in FED, then the relative combination of these two functions in the normal cornea should also be reassessed.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
2/9. Differential diagnosis of corneal oedema assisted by in vivo confocal microscopy.The purpose of this study was to demonstrate microstructural differences between clinically similar, but aetiologically different, cases of corneal oedema in four subjects. In vivo confocal microscopy highlighted oedema of the basal epithelium, prominent nerve-keratocyte interactions, and typical 'epithelialization' of the endothelium in a case of iridocorneal endothelial syndrome; however, a similar microstructural appearance was observed in a case of presumed herpetic disciform keratitis. The latter diagnosis was subsequently revised on this basis. Confocal examination of fuchs' endothelial dystrophy demonstrated oedema of the basal epithelium, prominent wing cells, anterior stromal alterations, fibrosis of Descemet's membrane and a typical 'strawberry' appearance of the endothelium. In contrast, in vivo microstructural examination of bilateral keratoconus with hydrops confirmed oedema mainly involving the epithelium and anterior stroma. In vivo confocal microscopy allows the clinician to observe the living cornea at a microstructural level and to better diagnose and differentiate borderline or unusual cases of corneal oedema.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
3/9. Analysis and documentation of progression of Fuchs corneal dystrophy with retroillumination photography.PURPOSE: Fuchs corneal dystrophy (FCD) is a degenerative disorder of the cornea that is characterized by the progressive accumulation of guttae, which are small excrescences of Descemet's membrane. We describe a method for documenting the location and number of guttae, and ask whether disease progression can be observed during relatively short periods. methods: patients with FCD were imaged by standard retroillumination photography with a slit lamp. Scanned photographs were analyzed by using NIH ImageJ software to determine the number of individual guttae and areas of confluence. RESULTS: In 4 FCD patients, photographs taken 23 to 30 months apart revealed that, once formed, individual guttae and their relative positions persisted during this period. Very few guttae disappeared, and the emergence of many new guttae was observed. Determination of the area with confluent guttae was used to quantify disease stage. CONCLUSIONS: Computer-assisted analysis of retroillumination photographs is proposed as an effective way to document the number and distribution of individual guttae. Although the disease typically progresses slowly during decades, we have been able to detect the formation of new guttae within only 2 years. This rapid assessment of disease progression could be used to measure phenotypic differences between genetic subtypes of FCD. It also could provide important baseline information and methodology for clinical trials of therapeutic options, should these become available.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
4/9. descemet membrane endothelial keratoplasty (DMEK).PURPOSE: To describe descemet membrane endothelial keratoplasty (DMEK) with organ cultured descemet membrane (DM) in a human cadaver eye model and a patient with Fuchs endothelial dystrophy. methods: In 10 human cadaver eyes and 1 patient eye, a 3.5-mm clear corneal tunnel incision was made. The anterior chamber was filled with air, and the DM was stripped off from the posterior stroma. From organ-cultured donor corneo-scleral rims, 9.0-mm-diameter "DM rolls" were harvested. Each donor DM roll was inserted into a recipient anterior chamber, positioned onto the posterior stroma, and kept in position by completely filling the anterior chamber with air for 30 minutes. RESULTS: In all recipient eyes, the donor DM maintained its position after a 30-minute air-fill of the anterior chamber followed by an air-liquid exchange. In the patient's eye, 1 week after transplantation, best-corrected visual acuity was 1.0 (20/20) with the patient's preoperative refraction, and the endothelial cell density averaged 2350 cells/mm. CONCLUSION: DMEK may provide quick visual rehabilitation in the treatment of corneal endothelial disorders by transplantation of an organ-cultured DM transplanted through a clear corneal tunnel incision. DMEK may be a highly accessible procedure to corneal surgeons, because donor DM sheets can be prepared from preserved corneo-scleral rims.- - - - - - - - - - ranking = 6keywords = membrane (Clic here for more details about this article) |
5/9. histology of posterior lamellar keratoplasty.PURPOSE: To report histology of a posterior lamellar graft performed to treat clinically significant endothelial disease in a patient with Fuchs dystrophy. methods: A 78-year-old patient with Fuchs dystrophy underwent posterior lamellar keratoplasty (PLK), the original form of endothelial keratoplasty performed with manual lamellar dissection of the recipient and donor corneas. Eighteen months later, the patient had herpes simplex virus keratitis and graft rejection episodes. One year after the infection resolved (2.5 years after PLK), penetrating keratoplasty was performed, and the excised corneal button was examined. RESULTS: Histopathologic evaluation of the corneal button showed no discernible interface, opacity, or gapping between the anterior host stromal tissue and PLK donor tissue or any signs of significant migration of donor endothelial cells onto recipient tissue. CONCLUSION: This PLK histology showed firm attachment with no visible interface between the posterior donor and anterior host stromal tissue. Surprisingly, no significant donor endothelial cell migration was detected on adjacent recipient tissue where descemet membrane had been excised or where endothelial cells were lost as a result of the procedure.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
6/9. Endothelial viral inclusions in Fuchs' corneal dystrophy.A case of Fuchs' corneal dystrophy is presented. The patient, a 70-year-old white woman, had bilateral decreasing vision, especially while reading and driving at night. Clinical features were characteristic of Fuchs' corneal dystrophy. Ultrastructural studies demonstrated findings in Descemet's membrane typical of those previously reported with numerous tactoids of fibrous long-spacing collagen in the posterior collagenous layer and in the guttata. In the endothelial cells were encapsulated ellipsoid viral particles, 400 nm long and 225 nm in diameter. They contained an outer and inner membrane with an electron-dense intervening region and a central dense core. Nucleocapsids were present in the endothelial cells and stromal keratocytes. The authors suggest that the pathogenesis of Fuchs' corneal dystrophy may be endothelial damage, and that in this case, the etiology is a viral infection.- - - - - - - - - - ranking = 2keywords = membrane (Clic here for more details about this article) |
7/9. Fuchs' corneal dystrophy. A clinicopathologic study of the variation in corneal edema.Corneal buttons from six patients with Fuchs' dystrophy had varying degrees of clinical edema measured in most cases by preoperative optical or ultrasonic pachymetry. These were sectioned in the operating room so that histologic correlations could be made. Histologically, marked thickening of Descemet's membrane and abnormal corneal endothelium corresponded to areas of severe clinical edema and were usually located in the central and paracentral regions. Descemet's membrane displayed multiple prominent guttata of varying size and shape, either facing the anterior chamber, or buried within multilaminar Descemet's membrane. In some corneas, aggregates of 10 nm fibrils were seen at the edges of guttata, corresponding to areas that stained for oxytalan fibrils. The endothelium was attenuated underlying the guttata. Clinical edema was not present unless accompanied by marked thickening of Descemet's membrane with multiple guttata and attenuation of corneal endothelium. The peripheral cornea was relatively clear clinically and showed minimal histologic changes.- - - - - - - - - - ranking = 4keywords = membrane (Clic here for more details about this article) |
8/9. Retinal periphlebitis as an early sign of bacterial endophthalmitis.Retinal periphlebitis appeared as an early sign of bacterial endophthalmitis in three patients, a 36-year-old man with bilateral Terson's syndrome who underwent vitrectomy for dense vitreous hemorrhage, a 78-year-old woman who had had intracapsular cataract extraction and penetrating keratoplasty after repair of a wound leak and pars plana anterior membranectomy, and an 18-year-old man who suffered an accidental penetrating ocular injury. staphylococcus organisms were recovered from vitreous samples in all three cases. Although recovery of useful vision is rare after postvitrectomy endophthalmitis, the first patient attained a final visual acuity of 20/50. The visual acuities of the second and third patients returned to 20/25 and 20/20 respectively. In an experimental primate (cynomolgus monkey) model of bacterial endophthalmitis, retinal periphlebitis developed early and closely resembled the clinical findings in humans. Histopathologic studies confirmed the presence of inflammatory cells that infiltrated the retinal venules.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |
9/9. Increased corneal scarring after phototherapeutic keratectomy in Fuchs' corneal dystrophy.PURPOSE: A 63-year-old female with Fuchs' endothelial corneal dystrophy, stromal edema and subepithelial scarring was inappropriately treated with phototherapeutic keratectomy, leading to a central focal circular corneal scar and decreased visual acuity that required penetrating keratoplasty. METHOD: The host corneal button was bisected and fixed in 10% formaldehyde and in glutaraldehyde immediately after its removal. RESULTS: light microscopy demonstrated a central area of absent Bowman's layer with a thin layer of subepithelial fibrosis, stromal corneal edema, and thickened Descemet's membrane. CONCLUSION: Correct estimation of differential ablation rates of tissue and shallow, repeated ablations followed by slit-lamp microscopy and/or videokeratography help prevent over-treatment.- - - - - - - - - - ranking = 1keywords = membrane (Clic here for more details about this article) |