Exploring the Relationship Between Central Corneal Thickness and Intraocular Pressure Among Nonglaucoma Patients in a General Ophthalmology Clinic, South East Nigeria

Abstract

Context: Glaucoma is an important cause of irreversible blindness and visual impairment in Nigeria. Studies have shown that intraocular pressure (IOP) is the only modifiable risk factor for glaucoma. The true IOP of an individual, in turn, is determined by the central corneal thickness (CCT). Aim: The aim of the study is to describe the relationship between IOP and CCT among nonglaucoma patients in Owerri, Imo State, Nigeria. Methods: This was a hospital-based, cross-sectional, analytical study done on nonglaucomatous patients aged 18 years and above. A comprehensive ocular examination was carried out for all participants and IOP was measured between 8 am and 12 noon to reduce the effect of diurnal variations. Results: Four hundred and twenty-two subjects with a mean age of 40.34 ± 14.468 years and a female to male ratio of 1.7:1 participated. The mean measured IOP was 16.77 ± 4.37 mmHg, and the mean CCT was 533.05 ± 33.92 μm. The mean corrected IOP was 17.61 ± 4.57 mmHg indicating a pattern of falsely low IOP. There was a positive, statistically significant correlation between IOP and CCT (P = 0.045). Conclusion: There was a positive correlation between IOP and CCT with the resultant effect that thin corneas presented with falsely low IOP and thick corneas with falsely high IOP. Routine CCT measurement in addition to IOP measurement should be done on every patient.