OCT-Based Diagnostic Criteria for Different Stages of Myopic Maculopathy

Abstract

To analyze the choroidal thickness (CT) of each type of myopic maculopathy, and to establish an OCT-based classification of myopic maculopathy. Retrospective, hospital-based, cross-sectional study. Highly myopic (HM) eyes that were examined by swept-source OCT. The CT was measured at the subfovea and at 3 mm nasal, temporal, superior, and inferior to the fovea. Myopic maculopathy was classified as tessellation, diffuse atrophy, patchy atrophy, and macular atrophy (MA) based on the fundus photographs. Diffuse atrophy was subdivided into peripapillary diffuse choroidal atrophy (PDCA) or macular diffuse choroidal atrophy (MDCA). The CT of each type of myopic maculopathy and cut-off value for diagnosis of diffuse atrophy. We studied 1487 eyes of 884 patients (mean age: 58 years; mean axial length [AxL]: 29.9 mm). Subfoveal CT decreased with an increase in the severity of the myopic maculopathy. The mean subfoveal CT in HM eyes with normal fundus was 274.5 μm, with tessellation was 129.1 μm, with PDCA was 84.6 μm, with MDCA was 50.2 μm, with patchy atrophy was 48.6 μm, with choroidal neovascularization-related MA was 27.3 μm, and with patchy atrophy-related MA was 3.5 μm. Using receiver operating characteristic curves, the optimal CT to predict the presence of PDCA was 56.5 μm nasally, and the CT to predict the presence of MDCA was 62 μm subfoveally. The subfoveal CT was not significantly different in eyes with MDCA and patchy atrophy. A decrease of the subfoveal CT was associated with an older age (P < 0.001), longer AxL (P < 0.001), presence of myopic maculopathy (P < 0.001), and presence of CNV (P= 0.002). A decrease of best-corrected visual acuity was not significantly associated with the subfoveal CT. Progressive and continuous choroidal thinning plays a key role in the progression from no maculopathy to tessellation and to diffuse atrophy. The cut-off value of CT can be used for diagnosing PDCA and MDCA. For progression from MDCA to patchy atrophy, factors other than further choroidal thinning such as Bruch membrane defect may be involved. The subfoveal CT was not a predictor of visual acuity in HM eyes without CNV.