Corneal thickness and corneal endothelium in normotensive subjects with unilateral exfoliation syndrome.

PURPOSE: To examine the central corneal thickness (CCT) and corneal endothelium in both eyes of patients with unilateral exfoliation syndrome (EXS). To determine the effect of CCT on the measurement of intraocular pressure (IOP). METHODS: In this cross-sectional clinical study, comparisons were made of CCT (Humphrey Ultrasonic Pachometer), corneal endothelial cells (Keeler-Konan contact specular microscope) and IOP (Goldmann applanation tonometer) between the exfoliative (E) and fellow nonexfoliative (NE) eyes in 40 normotensive patients with unilateral EXS. The CCT was used to obtain a corrected value for the IOP. RESULTS: The E eyes had significantly higher values for CCT (0.528+/-0.030 vs 0.523+/-0.032 mm, P<0.01) and IOP (15.7+/-3.6 vs 14.4+/-2.9 mmHg, P<0.001) than the fellow NE eyes. The paired E and NE eyes did not differ in endothelial cell density (2779+/-540 vs 2870+/-386 cells/mm2), in the coefficient of variation of cell size (0.25+/-0.03 vs 0.26+/-0.03) or in the frequency of hexagonal cells (80.5+/-6.5 vs 82.0+/-5.0%). After correcting IOP for CCT, the E eyes still had significantly higher IOP than the NE eyes (15.1+/-4.4 vs 14.2+/-3.7 mmHg, P<0.05). CONCLUSION: Normotensive eyes with early EXS did not have quantitative (cell density) or qualitative (variation in cell size, frequency of hexagonal cells) morphological changes in corneal endothelium, but had higher values for IOP and CCT. After correcting IOP for CCT, the E eyes still had significantly higher IOP than the fellow NE eyes.

Follow-up study of human corneal endothelial cells, photographed in vivo before enucleation and 20 years later in grafts.

PURPOSE: To evaluate the long-term (20-year) survival of transplanted human corneal endothelial cells. METHODS: The donor endothelium had been photographed 20 years ago with a specular microscope both before enucleation in the melanomatous eye and in situ after keratoplasty. The same donor endothelial cells were now photographed again 20 years later with a modern specular microscope to ascertain the morphology and cell density of the grafts. RESULTS: In the earlier study the mean postoperative endothelial cell density was 1357+/-543 cells/mm2, the average cell loss 11 months postoperatively being 48.2%; 20.5 years postoperatively the cell loss was 62.9% of the preoperative cell count. In our well-documented patient population the endothelial cell loss during the last 19 years had been only 14.7%, which amounts to a cell loss of less than 1% per year. CONCLUSION: In transplanted corneas, the main endothelial cell loss seems to take place during the first 1-2 postoperative years.

Effects of long-term contact lens wear on the corneal endothelium.

PURPOSE: To analyze the long-term effects of soft and hard (PMMA) contact lenses (CL) on the human corneal endothelium. METHODS: One hundred and one contact lens wearers with > or =10 years' wearing time and 50 healthy control subjects were examined with specular microscope. RESULTS: The mean corneal endothelial cell densities of the CL wearers (2846 cells/mm2) and of the control eyes (2940 cells/mm2) differed by 94 cells/mm2 (p<0.05). The mean values for the coefficient of variation (CV) differed significantly (p<0.0001); for all CL wearers: mean CV=0.31, vs. for controls: 0.22. The mean endothelial cell density of the eyes exposed to CL wear for more than 25 years (30 eyes) was 2575 cells/mm2 (mean CV: 0.36). Rather low densities (<2000 cells/mm2) were observed in 16 eyes of the CL group (8%). Cell densities less than 2500 cells/mm2 were observed in a total of 41 eyes (20%) in the CL group, whereas in the control group (100 eyes) all of the subjects, except one, had cell densities of more than 2500 cells/mm2 in both eyes. CONCLUSION: A subgroup of PMMA as well as soft contact lens wearers react not only with high pleomorphism and polymegethism but also with a decrease in endothelial cell density.