The Relationship Between Choroidal and Photoreceptor Layer Thickness With Visual Acuity in Highly Myopic Eyes

Abstract

PurposeThe aim of this study was to evaluate the choroidal and photoreceptor thickness in highly myopic eyes and its correlation with visual acuity.MethodsThis is a cross-sectional, observational study involving 57 eyes of 57 highly myopic subjects [spherical equivalent ≥ –6 diopters (D) or axial length ≥ 26 mm] seen in a tertiary institutional center. Eyes with any clinical evidence of maculopathy or amblyopia were excluded. All subjects underwent a refraction assessment, visual acuity, axial length measurement using the IOL Master, and full ocular assessment. Eyes were imaged using Spectralis Optical Coherence Tomography by one experienced operator. Two independent investigators manually measured subfoveal choroidal thickness (SFCT) and foveal photoreceptor thickness (FPT).ResultsThe mean SFCT was 195.88 ± 87.63 μm (range: 32–373) and mean FPT was 96.68 ± 11.23 μm (range: 67–100), after correction for ocular magnification. The best corrected visual acuity (BCVA) in LogMAR was negatively correlated with SFCT (r = –0.510, p = 0.001) and FPT (r = –0.397, p = 0.002) and positively correlated with age (r = 0.418, p = 0.001) and axial length (r = 0.551, p = 0.001). Multiple linear regression analysis showed that age, axial length, and corrected FPT were significant risk factors for poorer BCVA (p = 0.021, < 0.001, and 0.02, respectively).ConclusionFPT, age, and axial length are significant moderate predictive factors for poorer visual acuity in highly myopic eyes without myopic maculopathy. Thinner SFCT does not translate into poorer vision.

Comparative study of FLACS vs conventional phacoemulsification for cataract patients with high myopia

“…When imaging an eye with an AL of 24.46 mm, the actual scanning range t would be equal to s. When imaging eyes with other ALs, the real scan length t was determined by the equation t = (AL -1.82)/22.64 × s, as reported in our previous studies. 14,15 Image binarization techniques, performed with public domain software Image J (v. 1.51), were used to EDI foveal scans described by Agrawal et al previously to calculate choroidal vascularity index (CVI), total choroidal area (TCA), and luminal area (LA). First, we used a polygon tool to select the total choroidal area, which was added in the region-of-interest manager.…”