ASSESSMENT OF CENTRAL CORNEAL THICKNESS AND ITS RELATIONSHIP WITH INTRAOCULAR PRESSURE IN HEALTHY ADULTS

Abstract

Background: Central corneal thickness (CCT) is an important biometric parameter which affects applanation tonometry and consequently the clinical interpretation of intraocular pressure (IOP). In healthy adults, there can be inter-individual variation in corneal thickness that can result in overestimation or underestimation of IOP and influence glaucoma surveillance. Methods: This was a cross sectional study conducted at the hospital with 200 healthy adults aged 18-60 years. Visual acuity was tested, slit-lamp examination was performed, Goldmann applanation tonometry was conducted, and ultrasound pachymetry was performed. Glaucoma, ocular hypertension, corneal disease, previous ocular surgery, contact lens wear, diabetes and steroid use were excluded. The mean CCT and IOP were compared by age, sex and CCT category and correlation analysis was carried out. Results: The mean age was 36.8 +/- 11.4 years; 106 participants (53.0%) were female. Mean CCT was 536.7 +/- 32.8 micrometers in the right eye and 538.1 +/- 33.4 micrometers in the left eye. Mean IOP was 14.8 +/- 2.7 mmHg. IOP increased progressively across thin (<520 micrometers), average (520-560 micrometers), and thick (>560 micrometers) corneal groups (13.6 +/- 2.5, 14.7 +/- 2.4, and 16.2 +/- 2.8 mmHg, respectively; p<0.001). There was a moderate positive correlation between CCT and IOP (r=0.42, p<0.001). Conclusion: CCT was found to have a strong positive correlation with measured IOP in healthy adults, and should be used routinely to interpret borderline or elevated IOP.