| AIMS: To report the appearances of cornea guttata and fuchs' endothelial dystrophy from white light confocal microscopy. methods: Seven eyes of four consecutive patients with cornea guttata were prospectively examined. Of the seven eyes, three also had corneal oedema (Fuchs' dystrophy). In vivo white light tandem scanning confocal microscopy was performed in all eyes. Results were compared with non-contact specular microscopy. RESULTS: Specular microscopy was precluded by corneal oedema in one eye. In the remaining six eyes, it demonstrated typical changes including pleomorphism, polymegathism, and the presence of guttae appearing as dark bodies, some with a central bright reflex. In all seven eyes, confocal microscopy revealed the presence of round hyporeflective images with an occasional central highlight at the level of the endothelium. Changes in cell morphology and size were readily appreciated. CONCLUSION: By comparison with specular microscopy, the hyporeflective images with an occasional central highlight seen on confocal microscopy are consistent with the presence of guttae. Confocal microscopy may confirm the diagnosis of cornea guttata and fuchs' endothelial dystrophy by demonstrating the presence of guttae. This technique is especially valuable in cases of corneal oedema, where specular microscopy may fail to visualise the endothelium. However, specular microscopy should remain the method of choice to evaluate the endothelium, principally because it is easier to use. ( info) |
| 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. ( info) |
3/32. Denovo development of corneal guttae and Fuchs' dystrophy in corneal grafts. PURPOSE: To describe two cases of de novo development of corneal guttae and Fuchs' dystrophy in donor tissue following penetrating keratoplasty (PK) for unrelated conditions. methods: Two patients underwent PK for keratoconus and a disciform scar secondary to herpes simplex virus. They were followed clinically for a period of 16 and 11 years, respectively. Specular microscopy was used in one patient. RESULTS: Corneal guttae were first noted 10 years and 4 years following transplantation in the first and second patient, respectively. In both cases, the corneal guttae gradually increased in number, involving the central and temporal portions of the corneal graft There were no corneal guttae present in the host corneal rim or contralateral cornea of either patient. CONCLUSIONS: These cases provide evidence to suggest that some corneas may be genetically predetermined to develop corneal guttae and Fuchs' dystrophy many years before any changes can be clinically detected. ( info) |
4/32. Graft failure in human donor corneas due to transmission of herpes simplex virus. AIM: To report the clinical consequences of contamination of human donor corneas by herpes simplex virus (HSV) in organ culture. methods: Two patients without previous history of ocular HSV infection underwent penetrating keratoplasty (PK), one for keratoconus and the other for fuchs' endothelial dystrophy. One patient suffered primary graft failure while the other developed a persistent epithelial defect, ultimately resulting in graft failure. Viral culture of swabs taken from both corneas during the early postoperative period was undertaken. The failed donor corneas were examined histopathologically by immunohistochemistry (IHC) for HSV-1 antigens, transmission electron microscopy (TEM), and by polymerase chain reaction (PCR) for HSV dna. Both failed corneas were replaced within 6 weeks of the initial surgery. The records of the fellow donor corneas were also examined for evidence of infection. RESULTS: HSV was cultured from both corneas during the early postoperative period. histology of both donor corneas demonstrated a thickened corneal stroma with widespread necrosis of keratocytes and loss of endothelial cells. IHC showed keratocytes positive with antibodies to HSV-1 antigens. TEM demonstrated HSV-like viral particles within degenerating keratocytes. PCR performed on the failed corneal grafts was positive for HSV-1 dna, whereas PCR performed on the excised host corneal buttons was negative in both patients. Records of the fellow donor corneas showed that one cornea was successfully transplanted into another recipient after 18 days in organ culture, whilst the other was discarded because of extensive endothelial cell necrosis noted after 15 days in organ culture. CONCLUSION: HSV within a donor cornea may cause endothelial destruction in organ culture and both primary graft failure and ulcerative keratitis after transplantation. Endothelial necrosis of a donor cornea in culture also raises the possibility of HSV infection within the fellow cornea. ( info) |
5/32. 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. ( info) |
6/32. Anterior keratoconus associated with unilateral cornea guttata. PURPOSE: To describe a 30-year-old man with bilateral but asymmetric anterior keratoconus and unilateral cornea guttata in the eye with more advanced keratoconus. METHOD: Case report. RESULTS: The patient's keratoconus was diagnosed three or four years earlier. The keratoconus was confirmed by slit-lamp examination, keratometry, and computer-assisted topographic analysis. Cornea guttata were confirmed by clinical examination and specular microscopy. CONCLUSION: This is a rare case of unilateral cornea guttata associated with asymmetric keratoconus, showing severe guttate change only in the eye with more advanced keratoconus. ( info) |
7/32. Use of infant donor tissue for endokeratoplasty. Endokeratoplasty using an infant donor cornea was performed in an 81-year-old man with fuchs' endothelial dystrophy, corneal decompensation, and a history of cystoid macular edema in the left eye. The patient reported minimal discomfort after surgery, and the best spectacle-corrected visual acuity improved from 20/400 to 20/100 by the second postoperative month with resolution of the corneal edema. Endokeratoplasty using an infant cornea is a viable alternative to penetrating keratoplasty for corneal endothelial decompensation, and infant corneas may provide a new and potentially healthier source of tissue for corneal transplantation. ( info) |
8/32. VSX1: a gene for posterior polymorphous dystrophy and keratoconus. We identified mutations in the VSX1 homeobox gene for two distinct inherited corneal dystrophies; posterior polymorphous dystrophy (PPD) and keratoconus. One of the mutation (R166W) responsible for keratoconus altered the homeodomain and impaired dna binding. Two other sequence changes (L159M and G160D) were associated with keratoconus and PPD, respectively, and involved a region adjacent to the homeodomain. The G160D substitution, and a fourth defect affecting the highly conserved CVC domain (P247R), occurred in a child with very severe PPD who required a corneal transplant at 3 months of age. In this family, relatives with the G160D change alone had mild to moderate PPD, while P247R alone caused no corneal abnormalities. However, with either the G160D or P247R mutation, electroretinography detected abnormal function of the inner retina, where VSX1 is expressed. These data define the molecular basis of two important corneal dystrophies and reveal the importance of the CVC domain in the human retina. ( info) |
9/32. Corneal decompensation after laser in situ keratomileusis in fuchs' endothelial dystrophy. PURPOSE: To report corneal decompensation after laser in situ keratomileusis (LASIK) in a patient with fuchs' endothelial dystrophy.methods: Observational case report. RESULTS: A 47-year-old woman with cornea guttata without symptoms or findings of corneal edema had uneventful LASIK for -5.50 -0.50 x 150 in the right eye and -4.00 -1.25 x 170 in the left eye. Postoperatively, she developed corneal edema, with significant loss of best-corrected visual acuity in both eyes. Preoperative corneal thickness was 587 microm in the right eye and 549 microm in the left eye, measured by ultrasound pachymetry. These readings were 550 and 560 microm on day 67 postoperatively. Endothelial cell counts showed means of 1209 and 1661 cells/mm2 in the right and left eyes, respectively. CONCLUSION: Caution is suggested when considering LASIK in eyes with severe cornea guttata. ( info) |
10/32. Fixed dilated pupil (Urrets-Zavalia syndrome) in corneal dystrophies. PURPOSE: To report fixed dilated pupil following penetrating keratoplasty for corneal dystrophies. methods: Retrospective chart analysis of subjects who underwent penetrating keratoplasty for corneal dystrophies between 1998 and 2002 at our institute. RESULTS: Three of the subjects with fixed dilated pupils after penetrating keratoplasty had Macular corneal dystrophy and one subject had Fuchs Endothelial dystrophy. Fixed dilated pupils were noticed in the immediate postoperative period. None of the subjects had evidence for glaucoma either pre- or postoperatively. The follow up period ranged from 5 to 18 months. CONCLUSIONS: Fixed dilated pupil (Urrets-Zavalia syndrome) can occur after penetrating keratoplasty for corneal dystrophies and may not be limited to eyes with keratoconus as previously reported. ( info) |