[An analytical study of optical conditions of the elderly].

The visual acuity, refraction and related factors in 471 eyes 60-90 years of age were analyzed with the authors's statistical method for refractive data. The mean logarithmic visual acuity (Lv) of all eyes naked was 4.66 (equivalent to 20/44, or 6/13), and with corrections 5.03 (equivalent to 20/18.7, or 6/5.6). There was significant negative linear correlation between Lv and age (r = -0.9684), Lv = 5.7183-0.0095 x age. The percentages of hyperopia and myopia in the series were 47.8% and 39.7%, the mean refraction being +0.96 DS +0.78 DC and -1.29 DS -0.95 DC respectively. The percentage of mixed astigmatism was 7.86%, averaging +0.71 DC -0.74 DC. The mean refraction of all the patients was -0.05 +/- 2.90 DS -0.04 +/- 1.14 DC.