CORRELATION BETWEEN CORNEAL ASTIGMATISM AND CORNEAL TOPOGRAPHIC INDICES IN EARLY KERATOCONUS FOR EARLY DETECTION AND MANAGEMENT

Abstract

Objective: The Objective of this study is to find the correlation between the corneal astigmatism and corneal topographic indices in early keratoconus fore early detection and early management. Methodology: It was a prospective cross-sectional study which was conducted among the patients aged 5-25 years with moderate to high astigmatism like  2DC or greater. Approximately 70 eyes were selected using non probability sampling technique. Corneal Topographic and tomographic parameters were assessed to identify early keratoconus and their relationship with astigmatism was evaluated. Data was analyzed by using SPSS, with descriptive statistics, comparison of the parameters like corneal astigmatism, flat keratometric value K1, Steep keratometric value (K2), maximum keratometric value (Kmax) , Thinnest pachymetry point thickness (TCT), central corneal thickness (CCT) , Posterior Elevation (PE) among keratoconus-status groups, and correlation analysis between corneal astigmatism and other indices including K1, K2, Kmax, TCT ,CCT, PE and keratoconus status. Major findings: The keratoconus-suspect group was the largest group, comprising 29 eyes (41.4%), followed by the keratoconus-present group with 21 eyes (30.0%). Twenty eyes (28.6%) had no keratoconus. A significant differences was found among the keratoconus-status groups \for K1 (p=0.001), for K2 (p <0.001), for Kmax (p=0.009), for corneal astigmatism (p =0.020 ), and for TCT (p < 0.001). Corneal astigmatism showed significant correlations with K2 (p < 0.001), Kmax (p < 0.001), TCT (p = 0.009), CCT (p = 0.003), and with posterior elevation (p = 0.029), but not with K1 (p = 0.251). Conclusions: Corneal astigmatism was significantly associated with several corneal tomographic and topographic parameters, particularly K2, Kmax, TCT, CCT, and posterior elevation. The findings of this research suggest that corneal astigmatism could be a useful indicator for identifying early changings suggestive of keratoconus.