Correlation of Corneal Topographic Parameters with Visual Acuity in Patients with Keratoconus: A Cross-Sectional Observational Study
Abstract
Background Keratoconus is a progressive corneal ectatic disorder characterized by thinning, steepening, irregular astigmatism, and reduced visual acuity. Corneal topography provides quantitative indices for assessing structural severity and functional impact. Objectives To assess the correlation of corneal topographic parameters with best-corrected visual acuity (BCVA) in patients with keratoconus Methods This hospital-based cross-sectional observational study included 100 consecutively enrolled patients with keratoconus at Rajiv Gandhi Institute of Medical Sciences, Adilabad, from August 2025 to January 2026. One eye per patient was analysed. BCVA was recorded in logMAR units. Keratometric, pachymetric, astigmatic, and elevation parameters were assessed by corneal topography. Pearson correlation analysis evaluated associations with BCVA. Results Mean age was 23.6 ± 6.8 years; 58.0% were male. Mild, moderate, and severe keratoconus accounted for 26.0%, 44.0%, and 30.0%, respectively. Mean BCVA was 0.42 ± 0.28 logMAR, Kmax 56.9 ± 8.4 D, and thinnest pachymetry 439.5 ± 46.2 µm. BCVA worsened from 0.18 ± 0.10 logMAR in mild disease to 0.68 ± 0.27 logMAR in severe disease (p < 0.001). Kmax had the strongest positive correlation with BCVA (r = 0.71, p < 0.001), whereas thinnest pachymetry had the strongest negative correlation (r = −0.66, p < 0.001). K2 (r = 0.64), posterior elevation (r = 0.62), anterior elevation (r = 0.57), central corneal thickness (r = −0.54), K1 (r = 0.52), and corneal astigmatism (r = 0.48) were also significant (all p < 0.001). Conclusion Greater corneal steepening and thinning were significantly associated with poorer BCVA. Kmax and thinnest pachymetry showed the strongest correlations and may serve as useful structural indicators during assessment and follow-up. Recommendations Routine topographic monitoring, particularly Kmax and pachymetry, should support severity grading, follow-up, visual rehabilitation, and timely referral for cross-linking when clinically indicated.