Diurnal variation of central corneal thickness and intraocular pressure in eyes with pseudoexfoliation

PURPOSE: Pseudoexfoliation syndrome (PXS) is an age related microfibrillopathy characterized by deposition of whitish flaky material over various ocular tissues. PXS eyes are known to have thinner corneas and thus can lead to an underestimation in intraocular pressure measurement. The purpose of this study was to find if there is any variation in central corneal thickness and intraocular pressure in PXS eyes and if there was any relationship between them. METHODS: A prospective observational study was done on 141 eyes of 85 patients with PXS without glaucoma between November 2015 to April 2017 in the department of Ophthalmology in a tertiary hospital. CCT and IOP were measured by a handheld ultrasonic pachymeter (DGH Technology INC. Pachette 2, USA) and Goldmann applanation tonometer respectively at 4 different times during office hours. RESULTS: A significant reduction of about 10 μm in mean CCT and 1.4 mmHg in mean IOP was noted over the 4 sessions which was statistically significant (P < 0.001). A significant correlation exists between IOP and CCT in PXS eyes at all times during the day (P < 0.001). CONCLUSION: The CCT measurements show significant thinning throughout the day, similar drop in IOP was also noted. Our study shows that there is a significant correlation between diurnal variation of CCT and IOP. Hence, it is prudent to measure CCT along with IOP at all times.