Correlation of myopia severity with visual performance

Purpose To describe visual performance in high myopia. Methods In this cross-sectional study, 148 emmetropes [spherical equivalent (SE) - 0.50 to + 1.00 D] and 564 high myopes [SE <= - 6.00 D] were categorised into three groups (Group 1: SE - 6.00 to > - 8.00 D; Group 2: SE - 8.00 to > - 10.00 D; and Group 3: SE <= - 10.00 D). Multivariate regression analyses adjusting for age and ethnicity examined the relationship between corrected distance visual acuity (CDVA) [photopic, mesopic and super vision test-night vision goggles (SVT-NVG)] and contrast sensitivity (CS)] (mesopic and SVT-NVG) with SE and axial length (AL). Results Mean age of subjects was 21.07 +/- 1.17 years, and majority were Chinese (91.9%). Mean SE was 0.10 +/- 0.23 D (emmetropes) and - 8.76 +/- 2.04 D (high myopes), p < 0.001. Higher degrees of myopia were associated with reduced CDVA and CS, and increased AL (all p < 0.001). Among high myopes, Group 1 had the highest proportion of subjects with good CDVA (photopic <= 0.00 LogMAR, mesopic <= 0.00 LogMAR and NVG <= 0.10 LogMAR) and CS (mesopic >= 0.75 LogCS and NVG >= 0.35 LogCS) compared with Groups 2 and 3 (all p < 0.001). Among high myopes with good VA (photopic <= 0.00 LogMAR, mesopic <= 0.00 LogMAR and NVG <= 0.10 LogMAR), Group 1 also had the highest proportion of subjects who achieved mesopic >= 0.75 LogCS and NVG >= 0.35 LogCS (both p < 0.001). Multivariate analyses demonstrated that reduced VA and CS were associated with decreased SE and increased AL (all p < 0.001). Conclusions High myopia is associated with reduced VA and reduced CS.