Optical Compensation for Night Myopia Based on Dark Focus and AC/C Ratio

摘要

To determine whether individual differences in dark focus and convergenceaccommodation to convergence (CA/C) ratio can be used to prescribe the best optical correction for night myopia. The best correction for night myopia was obtained by measuring visual acuity and contrast sensitivity across a range of lens powers and luminances. Dark focus was measured with an infrared optometer, and CA/C ratio was measured--with an infrared optometer and eyetracker. Only young subjects were used (mean age = 254 years). Optimal lens power was significantly correlated with dark focus, regardless of CA/C ratio. However, the slope of the regression line relating lens power to dark focus was steeper for subjects with CA/C ratios less than 0.4 diopters/meter angle (D/MA, n = 7) than for subjects with CA/C ratios greater than 0.4 D/MA (n-= 9). The mean CA/C ratio for the entire sample (n = 16) was 0.59 D/MA.