The Role of Corneal Volume Distribution and Percentage Increase in Volume in Detection of Mild and Moderate Keratoconus

To investigate the validity of Pentacam derived parameters like corneal volume distribution and percentage increase in volume in differentiation of mild to moderate keratoconus from normal corneas Forty eyes with mild to moderate keratoconus and 200 normal eyes were studied by Pentacam. Corneal volume was calculated within diameters from 1.0 to 7.0 mm with 0.5 mm steps centered on the thinnest point to create the corneal volume distribution. The percentage increase in volume was calculated for each position of the corneal volume distribution from their first value. Statistical analysis was done using the Mann-Whitney test to compare mean levels of two groups and the Wilcoxon test for two consecutive measurements. Statistically significant differences were observed between the keratoconic and normal corneas (P<0.01) in all positions of corneal volume distribution and in the percentage increase in volume. The differences between the curves of the two groups were more significant in 3 mm diameter and further. There are significant difference between corneal volume distribution and percentage increase in volume in keratoconic and normal corneas and could serve as valid indices to diagnose mild and moderate forms of keratoconus.