Effect of Central Corneal Thickness on Intra Ocular Pressure Measured by NCT and GAT

Dr. Nithisha T. M, Dr. Kaushal Bhat, Dr. Mayuri Kathariya

Abstract: Purpose: To assess the effect of central corneal thickness (CCT) on intra ocular pressure measured by non-contact tonometer and goldmann applanation tonometer. Method: A hospital based observational study done on 60 eyes of 30 patients aged 18-40 years, without comorbidities and without history of ocular trauma. CCT was measured first using Tomey Specular microscope EM-4000, NCT (non-contact tonometer) using air puff Frey TN-100, followed by GAT (goldmann applanation tonometer). Results: Pearson Correlation:0.59 (p-value < 0.001), indicates a moderate positive correlation, confirming that higher CCT is associated with higher GAT readings. Linear Regression: Slope of 0.12 and R-squared of 0.35, suggests that about 35% of the variability in GAT readings is explained by CCT. Pearson Correlation: 0.84 (p-value < 0.001), indicating a strong positive correlation indicating a strong association between higher CCT and higher NCT readings. Linear Regression: Slope of 0.24 and R-squared of 0.71, shows that 71% of the variability in NCT readings can be explained by CCT. CCT significantly impacts both GAT and NCT readings, with NCT readings being more strongly affected by changes in CCT.

Keywords: CCT (Central corneal thickness), NCT (Non-Contact Tonometer), GAT (Goldmann Applanation Tonometer), IOP (Intra Ocular Pressure)