Visual function correlates with foveal slope, retinal and choroidal thickness on optical coherence tomography in type 2 Macular Telangiectasia

Abstract

ABSTRACT Purpose To correlate the foveal slope angle (FSA), retinal (RT) and choroidal (CT) thickness measured using optical coherence tomography (OCT) across different stages of type 2 macular telangiectasia (MacTel) with best-corrected visual acuity (BCVA). Methods A cross-sectional study of 182 gradable quality macular OCT images of 49 patients with type 2 MacTel was carried out. RT was measured on the Spectralis OCT machine from ETDRS (Early Treatment Diabetic Retinopathy Study) retinal thickness map and later used for calculating FSA. RT and CT were measured at 500-µm intervals up to 1500 µm from foveal centre manually. The change in RT, CT and FSA across five stages of type 2 MacTel was assessed. The measurements were correlated with BCVA. Results The FSA, RT and CT were calculated quadrantwise and stagewise. The FSA and RT showed a significant negative correlation with disease stage and BCVA (p < .05) in all four quadrants. No significant correlation was noted between CT and BCVA. Multivariate linear regression analysis identified the temporal FSA to correlate best with BCVA. Conclusion BCVA correlates best with temporal FSA. Smaller the temporal FSA, poorer the vision.