Correlating central corneal thickness and intraocular pressure in ocular hypertension and glaucoma

Abstract

Objective: This study determined the relationship between central corneal thickness (CCT) and intraocular pressure (IOP) among patients with ocular hypertension (OHT) and glaucoma.

Methods: Patients diagnosed with OHT and primary glaucoma were recruited from the Glaucoma Clinic of the University of the Philippines–Philippine General Hospital. All underwent a comprehensive eye exam including determination of CCT by ultrasonic pachymetry, measurement of IOP by Goldmann applanation tonometry, axial-length determination and anterior-chamber-depth measurement by biometry. Statistical analyses included chi square, Kruskal Wallis analysis of variance, Pearson correlation, and linear regression. A conversion factor for the corrected IOP was subsequently obtained.

Results: Eighty-three eyes of 47 patients were included. CCT was thickest among patients with OHT (588 µm), followed by primary open-angle glaucoma (538 µm), angle-closure glaucoma (531 µm), and normal-tension glaucoma (526 µm). A moderate positive correlation between CCT and IOP was seen among patients with OHT (r = 0.55, p = 0.04). An increase of 5.3 mm Hg per 100 µm increase in CCT was noted.

Conclusion: Central corneal thickness among Filipino patients with OHT was thicker than those with glaucoma. A direct correlation was seen between CCT and IOP of these patients.