Association of central corneal thickness and 24-hour intraocular pressure fluctuation

PURPOSE: To evaluate the association between office-hour central corneal thickness (CCT) and 24-hour intraocular pressure (IOP) fluctuation in patients with glaucoma. DESIGN: Observational case-control study. METHODS: Measurements of IOP were obtained every 2 hours during a 24-hour period from 52 untreated glaucoma patients and 29 age-matched normal control subjects housed in a sleep laboratory. Habitual IOP measurements were obtained using a pneumatonometer in the sitting positions during the diurnal/wake period (7 AM to 11 PM) and in the supine position during the nocturnal/sleep period (11 PM to 7 AM). CCT was measured in all subjects using ultrasound pachymetry once during office hours. The association between IOP fluctuation (peak IOP-trough IOP) during the 24-hour period and the office-hour CCT was assessed in both glaucoma patients and healthy age-matched controls using Spearman rank order correlation. RESULTS: There was no statistically significant correlation between IOP fluctuation and CCT in glaucomatous (P=0.405) and normal subjects (P=0.456). CONCLUSIONS: Twenty-four-hour IOP fluctuations were not correlated with single CCT measurements taken during office hours in glaucoma patients.