Prediction of Best-Corrected Visual Acuity With Swept-Source Optical Coherence Tomography Parameters in Keratoconus

Abstract

Purpose: This study aimed to predict the best-corrected visual acuity (BCVA) based on swept-source optical coherence tomography (SS-OCT) parameters in eyes with keratoconus. Methods: We retrospectively reviewed 135 eyes of 135 patients with keratoconus (mean age: 31.9 ± 12.4 years). The average keratometry value and BCVA (logarithm of the minimal angle of resolution [Snellen]) were 48.68 ± 5.44 diopter and 0.20 ± 0.36 (20/25), respectively. Eleven parameters were calculated using SS-OCT. Apart from the corneal height and elevation, all the other parameters were calculated from both anterior and posterior corneal OCT data. The patients were divided into 2 groups, 1 for creating the prediction equation (prediction group, 86 eyes) and another for verifying the equation (verification group, 49 eyes). In the former, individual correlations between the BCVA and SS-OCT parameters were analyzed. A stepwise multiple regression analysis was performed with the BCVA as a dependent variable and SS-OCT parameters as independent variables. After its creation, the accuracy of the prediction equation was verified in the verification group. Results: All the parameters, except for age and total corneal cylinder, showed statistically significant correlations with BCVA (P < 0.0001). Using the stepwise multiple regression analysis, we selected 2 explanatory variables: root mean square of anterior corneal elevation (standardized regression coefficient: 1.221; P < 0.0001) and total coma aberration (standardized regression coefficient: −0.575; P = 0.001; adjusted R2 = 0.546). The prediction was correct in 84.6% of the eyes within ±1 line of Snellen BCVA. Conclusions: Using the equation we derived from SS-OCT parameters is a promising method to predict visual function in patients with keratoconus.

A model of visual limitation in patients with keratoconus

“…According to previous authors 21 , 22 , Kmax was the topographic parameter that explains the highest percentage of visual acuity. MCT was found to be a useful parameter for early diagnosis and progression of keratoconus patients.…”

“…Total RMS and vertical coma correlated better with loss of vision. Esaka et al 22 found that RMS of corneal elevation (RMSE) (r = 0.699) and total coma aberration (r = − 0.513) were related with BSCVA (logMAR). In our study, correlations were found among V.L.…”

“…However, it would not modify the visual acuity of these patients. Esaka et al 22 formulated an equation to calculate BSCVA with RMS of corneal elevation (RMSE) and total coma aberration.…”

“…Esaka et al . 22 formulated an equation to calculate BSCVA with RMS of corneal elevation (RMSE) and total coma aberration.…”

“…Topography is essential for the study of keratoconus, and its variables can be determinant of the patient visual acuity. The quantity and quality of vision are correlated with topographic indices 21 , 22 . Several studies have demonstrated the relationship between severe V.L.…”