Visual Acuity in Pathological Myopia Is Correlated With the Photoreceptor Myoid and Ellipsoid Zone Thickness and Affected by Choroid Thickness

PURPOSE. To quantify the thickness of the outer retinal sublayers and choroid in pathological myopia and examine associations between these factors and best-corrected visual acuity (BCVA). METHODS. The cohort was composed of 21 eyes with emmetropia and 70 eyes with high myopia (49 simple high myopia; 21 pathological myopia). Optical coherence tomography images were segmented to determine macular thicknesses of the choroid and the following outer retinal sublayers: outer plexiform layer (OPL), Henle fiber layer and outer nuclear layer (HFL thorn ONL), myoid and ellipsoid zone (MEZ), outer segment of photoreceptors (OS), and interdigitation zone and RPE/Bruch complex (IZ + RPE). Correlations between BCVA and thickness of the outer retinal sublayers and choroid were determined. RESULTS. In pathological myopia, the choroid, HFL thorn ONL, MEZ, and IZ thorn RPE were thinner than in emmetropia and simple high myopia (P < 0.05). Simple and multiple regression models showed that MEZ thickness was correlated with BCVA (both P < 0.001). The relationship between MEZ thickness and BCVA varied with choroidal thickness (P = 0.006). For a constant MEZ thickness, thinner choroids were associated with worse vision. In the final multiple regression predictive model, MEZ thickness, choroidal thickness, and interaction between MEZ and choroidal thickness (all P < 0.001) were predictors of BCVA. CONCLUSIONS. Outer retinal alterations, especially thinning of the MEZ, occurred in pathological myopia. The MEZ thickness was associated with BCVA, and this relationship was affected by choroidal thickness.