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

Abstract

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.