[Early clinical evaluation of contrast visual acuity in patients with age- related cataract]

To evaluate the changes of the contrast visual acuity (CVA) in early agerelated cataract patients.

Case-controlled study. One hundred and four eyes of 52 age-related cataract patients, with the best corrected visual acuity equal to or more than 0.8, equivalent spherical diopters of -3.00 to 3.00 DS and astigmatic diopters of -1.50 to 1.50 DC, were selected as the cataract group. Another 104 eyes of 52 normal adults, with the best corrected visual acuity equal to or more than 0.8, equivalent spherical diopters of -3.00 to 3.00 DS and astigmatic diopters of -1.50 to 1.50 DC, were selected as the control group. They were paired according to sex, the similar age and the best corrected visual acuity. After eye and refractive examinations, all examinees received the CVA measurements in different contrast levels between the optotypes and background (100%, 25%, 10% and 5%) in the dark room by the multifunction visual acuity chart. SPSS 18.0 software package was used for paired t test.

In the cataract group, CVA decreased more significantly than the control group. OD: 0.99 ± 0.26, 0.59 ± 0.23, 0.38 ± 0.19, 0.23 ± 0.12. OS: 0.98 ± 0.28, 0.59 ± 0.18, 0.38 ± 0.14, 0.23 ± 0.10. OU: 1.15 ± 0.26, 0.73 ± 0.20, 0.49 ± 0.16, 0.30 ± 0.10 (OD: t = -6.49, -7.25, -7.57, -5.45. OS: t = -5.78, -7.51, -6.41, -7.16. OU: t = -4.33, -7.60, -7.53, -9.75, P < 0.01). There was a significant decrease in different degrees of cortical cataract (F100% = 50.18, P = 0.000. F25% = 23.08, P = 0.000. F10% = 20.17, P = 0.000. F5% = 13.42, P = 0.000). There was a significant decrease in different degrees of cortical cataract compared with the control group (C1: t = -6.49, -7.25, -7.57, -5.45, P < 0.05. C2: t = -5.78, -7.51, -6.41, -7.16, P < 0.01. C3: t = -4.33, -7.60, -7.53, -9.75, P < 0.01).

CVA was more reliable than the best corrected visual acuity in evaluating vision function in patients with early age-related cataract.