Dr. Seema Bhosale, Dr. Vijay Shetty, Dr. Suhas Haldipurkar, Dr. Ravish Vaishnav
Purpose:To assess distribution and correlation of Anterior(ACA) and posterior(PCA) corneal astigmatism in keratoconus(KC)patients.
Methods:Secondary data analysis of 43 eyes of 30 patients of KC,classified by Amsler Krumeich staging and Pentacam data was used to assess ACA and PCA.
Results: Mean ACA and PCA was 3.05D*90.42 and 0.50D*179.70 in KC,1.0D*89.45 and 0.25D*92.61 in age matched normals. Astigmatic orientation was With the rule astigmatism(WTR) for ACA and PCA in KC against WTR for ACA and Against the rule astigmatism (ATR)for PCA in normals.A trend of increasing ACA with increasing severity was noted in KC with highest ACA in stage 4 (4.75D @75.6).1 unit change in ACA correlated with PCA by -0.22 unit change in Stage1,-0.12 unit change in stage 2 and -0.32 unit change in stage 3(p<0.001) with no correlation in stage 4.
Conclusion: PCA showed opposite orientation in KC as compared to Normals. A linear correlation was noted between ACA and PCA in all stages except stage 4 in KC.