A study for the assessment of central corneal thickness and visual field defects in patients of primary open-angle glaucoma

Abstract

Purpose: The aim of this study is to assess the central corneal thickness (CCT) and visual field (VF) changes in patients of primary open-angle glaucoma (POAG) and the influence of CCT on glaucomatous damage in glaucoma clinic of Dr. R. P. G. M. C Kangra at Tanda. Materials and Methods: This cross-sectional study conducted on 103 eyes of 58 patients of POAG- >40 years. All patients underwent a complete eye examination including Goldmann applanation tonometry, CCT measurement through ultrasonic pachymeter, stereoscopic disc photography, retinal nerve fiber layer (RNFL) photography, and automated perimetry. Correlation of CCT with age, gender, intraocular pressure (IOP), advanced glaucoma intervention study (AGIS) score, VF parameters (mean deviation, pattern standard deviation [PSD]), vertical cup-disc ratio, average RNFL, and number of antiglaucoma medications was analyzed. The patients were divided into two groups – thin and thick CCT taking a reference range of 529 μm derived from a previous study done in same area with larger sample size. Pearson correlation was used for correlation coefficient and a value of P < 0.05 was considered statistically significant. Results: Thin CCT was significantly correlated with IOP (r = 0.28, P = 0.004). Thin CCT was also significantly associated with worsened PSD of VF (r = 0.25, P = 0.02). The mean AGIS score was more (8.07 ± 5.52) in patients with thin CCT (<529 μm) in comparison (5.96 ± 6.10) to patients with thick CCT (>529 μm) which was statistically significant (P < 0.05). Conclusion: CCT is a significant risk factor for glaucomatous VF loss. Patients with thinner CCT are more likely to have advanced VF defects in comparison to patients with thick CCT.