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

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 R = 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.

Quantitative evaluation of night vision and correlation of refractive and topographical parameters with glare after orthokeratology.

PURPOSE: To evaluate night vision disturbance and investigate correlations between pre- and post-treatment parameters and glare scores in orthokeratology patients. METHODS: Twenty-eight right eyes of 28 patients were enrolled in this study. Corneal topography and a night vision test (NVT) to evaluate the extent of glare were performed after orthokeratology. From the corneal topography, two indices [surface regularity index (SRI) and surface asymmetry index (SAI)] were calculated. Fourier analysis was performed on the topographic data from the central 6 mm, and data were decomposed into asymmetric and higher order components for analysis. RESULTS: There was no correlation between the glare score and pre-treatment keratometric value, pre-treatment cylinder, post-treatment sphere, and post-treatment cylinder. However, there was a statistically significant correlation between pre-treatment sphere and glare score (Pearson correlation coefficient, r = -0.54, p < 0.01). SRI and SAI significantly correlated with glare score (SRI: r = 0.52, p < 0.01, SAI: r = 0.41, p < 0.05). Higher order and asymmetric components were also significantly correlated with glare score (asymmetry: r = 0.61, p < 0.01, higher order: r = 0.67, p < 0.001). CONCLUSIONS: The glare score was significantly correlated with corneal irregularity, and appeared to be a beneficial parameter for assessment of night vision performance in patients receiving orthokeratology.