Effect of Aging on Optical Quality and Intraocular Scattering Using the Double-Pass Instrument

Purpose: To assess the effect of aging on optical quality in a normal population. Methods: We prospectively examined 100 normal eyes of 100 healthy volunteers (50 men, 50 women; ages, 20-69 years; mean age +/- standard deviation, 44.6 +/- 15.5 years). We quantitatively assessed the values of MTF cutoff frequency, Strehl ratio, and objective scattering index (OSI), using an Optical Quality Analysis System (TM) (Visiometrics, Terrassa, Spain). We took these measurements three times each, and the mean value obtained was used for statistical analysis. We investigated the relationships between subject age and these optical quality parameters. Results: The mean MTF cutoff frequency, Strehl ratio, and OSI, were 27.76 +/- 8.41, 0.17 +/- 0.05, and 1.29 +/- 0.76 cycles/degree, respectively. We found a significant negative correlation between subject age and MTF cutoff frequency (Pearson's correlation coefficient r = -0.606, p < 0.001), and between age and Strehl ratio (r = -0.649, p < 0.001). We also found a significant positive correlation between subject age and OSI (r = 0.691, p < 0.001). Conclusions: The MTF cutoff frequency and the Strehl ratio are significantly decreased, and the OSI is significantly increased, by aging, indicating that the optical quality of the eye is degraded in older subjects.