Effect of Scattering and Aberrations on Visual Acuity for Band Keratopathy.

Abstract

The progressive accumulation of the calcification may deteriorate corneal transparency, especially in the interpalpebral area, and subsequent visual performance for patients with band keratopathy. However, the detailed quantitative analysis of light scattering or higher-order aberrations on visual performance for these patients so far has not been elucidated. The aim of this study was to assess the relationship of intraocular forward scattering, corneal backward scattering, and corneal higher-order aberrations with visual acuity in eyes with band keratopathy. This prospective study comprised 27 eyes of 27 consecutive patients who were diagnosed as having band keratopathy and age-matched 27 eyes of 27 healthy subjects. We quantitatively assessed objective scattering index using the double-pass instrument (Optical Quality Analysis System II; Visiometrics, Terrassa, Spain), corneal densitometry using the Scheimpflug rotating camera (Pentacam HR; Oculus, Wetzlar, Germany), and corneal higher-order aberrations using the Hartmann-Shack aberrometry (KR-9000; Topcon, Tokyo, Japan). The mean objective scattering index, corneal densitometry, corneal higher-order aberrations, and logarithm of the minimal angle of resolution (logMAR) visual acuity in eyes with band keratopathy were 5.14 ± 3.11, 36.42 ± 10.55 gray-scale units, 0.33 ± 0.10 μm, and 0.03 ± 0.11 logMAR, respectively. These parameters were significantly larger in the band keratopathy group than in those in the control group (Mann-Whitney U test, P < .001). We found significant correlations of visual acuity with the objective scattering index (Spearman correlation coefficient, r = 0.465, P = .015), but no significant association with the corneal densitometry (r = 0.082, P = .683) or with corneal higher-order aberrations (r = -0.073, P = .718), in eyes having band keratopathy. Intraocular forward scattering, corneal backward scattering, and corneal higher-order aberrations in eyes with band keratopathy were significantly higher than those in normal eyes. Visual acuity was significantly correlated with intraocular forward scattering, but not with corneal backward scattering or corneal aberrations in the band keratopathy group, suggesting that intraocular forward scattering plays a vital role in visual performance in eyes with band keratopathy.