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 + 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 + ONL, MEZ, and IZ + 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.