Analysis of related factors of optical quality in healthy Chinese adults: a community-based population study.

Background: In recent years, visual quality has been extensively investigated in various conditions. In this community-based population study, we analyzed the effects of aging, refraction, and Lens Opacification Classification System III (LOCSIII) score on retinal imaging quality in healthy Chinese adults.

Methods: This cross-sectional study was conducted on sub-group subjects from The Handan Eye Study between October 2012 and January 2013. Healthy subjects over 30-years-old with logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity (BCVA) less than 0 were included. Retinal image quality was measured by optical quality analysis system (OQAS) and recorded as modulation transfer function cutoff frequency (MTFcutoff), OQAS value (OV) 100%, OV20%, OV9%, Strehl ratio (SR), and objective scatter index (OSI). The correlation between age, spherical equivalent refraction (SE), LOCSIII score, and optical quality parameters were investigated by multivariate analysis.

Results: Among 1108 verified subjects, 690 subjects (1380 eyes) met the inclusion criteria. Their age ranged from 30 to 76 years, SE ranged from -4.75 to 2.75 D. They were divided into five age groups (30-39, 40-49, 50-59, 60-69, and ≥70 years) for further analysis. After multivariate analysis by mixed-effect linear model, SR (t =  -3.03, P = 0.002), OV20% (t = -2.39, P = 0.017), and OV9% (t = -3.16, P = 0.001) significantly decreased with the increasing age, whereas logMAR BCVA (t = 4.42, P < 0.001) and OSI (t = 4.46, P < 0.001) significantly increased with age. As SE increased, SR (t = 2.74, P = 0.01), OV20% (t = 2.31, P = 0.02), and OV9% (t = 2.79, P = 0.005) significantly elevated, and OSI (t = -3.38, P < 0.001) significantly decreased. With the increase in cortical opacity score, all optical quality parameters except for SR significantly decreased, including MTFcutoff (t = -2.78, P = 0.01), OV100% (t = -2.78, P = 0.005), OV20% (t = -2.60, P = 0.009), and OV9% (t = -2.05, P = 0.040). As posterior sub capsular opacity score increased, MTFcutoff (t = -2.40, P = 0.02) and OV100% (t = -2.40, P = 0.01) significantly decreased, while OSI (t = 7.56, P < 0.001) significantly increased.

Conclusions: In healthy Chinese adult population, optical quality-related parameters significantly decrease with the increasing age, and OSI significantly increases with age. In normal BCVA subjects, optical quality is significantly impacted by cortical and posterior sub capsular opacity rather than by nuclear opacity.