Retinal and choroidal thickness measurement in myopic eyes by spectral domain optical coherence tomography and enhanced depth imaging: OCT

Background: Early detection and timely intervention of high myopia and associated maculopathy can prevent long term complications in myopics. Measurement of retinal thickness by Spectral Domain-Occular Coherence Tomography (SD-OCT) and choroidal thickness by Enhanced Depth Imaging- Occular Coherence Tomography (EDI-OCT) was undertaken in this study.Material and Methods: Total 92 patients (46 high myopic, 46 normal vision as controls) recruited for the study. Correlation among retinal and choroidal thickness with age, refractive error in dioptres and co-relation of visual acuity measured in log MAR with choroidal and retinal thickness were analyzed with linear mixed models.Results: The mean age of the 46 patients with high myopia was 35.3 + 7.941, the mean axial length was 26.73 + 1.584 mm in myopes. The mean subfield RT thickness was found to be 240.72 + 32.581μm. The subfoveal CT was found to be 115 + 87.8 μm. The mean photoreceptor layer thickness including the RPE layer was 98.6 + 9.8 μm.Conclusion: OCT was helpful in detecting early macular changes in the myopic retina, which could be precursors to various forms of myopic maculopathy. OCT can serve as a useful guideline in early diagnosis, management, prognostication and research for high myopia patients.