Objective optical quality and intraocular scattering in myopic adults

Purpose: To evaluate objective optical quality and intraocular scattering in adults with myopia.

Methods: This was a cross-sectional study. Patients between 18 and 40 years of age were recruited from those undergoing routine preoperative examinations prior to myopic refractive surgery. The spherical equivalent refraction (SE) ranged from -14.25 to -0.63 diopters (D). Right eyes of 274 subjects were included for factor analyses: 25 eyes were super-high myopia (SE < -9 D), 88 eyes were high myopia (-6 D > SE ≥ -9 D),133 eyes were moderate myopia (-3 D > SE ≥ -6 D), and 28 eyes were low myopia (SE ≥ -3 D). A double-pass system was used to measure the modulation transfer function cutoff frequency (MTFcutoff) and objective scatter index (OSI).

Results: Mean MTFcutoff was 32.38 ± 9.73 and 27.61 ± 8.11 cycles per degree (cyc/deg) in the high and super-high myopia groups, significantly lower than 39.92 ± 10.53 and 37.39 ± 8.74 cyc/deg in the low and moderate groups (P < 0.01). Mean OSI was 0.89 ± 0.61 and 1.33 ± 0.65 in the high and super-high myopia groups, significantly higher than in the low and moderate groups, 0.50 ± 0.39 and 0.57 ± 0.44 (P < 0.01). No significant difference was found between the low myopia and the moderate myopia group in any of the parameters (P > 0.05). Other factors such as eye side, sex, and age did not significantly affect optical quality parameters or OSI in this study population (P > 0.05).

Conclusions: Optical quality and intraocular scattering varied among individuals with myopia. High myopia has more influence on retinal image quality and scattering than moderate and low myopia. Our study also helps to establish MTFcutoff and OSI standards for Chinese refractive surgery candidates.