Contrast visual acuities in cataract patients. I. Comparison with normal subjects

Contrast sensitivity and glare sensitivity are often abnormal in cataract patients. However, despite significant subjective complaints, relatively good visual acuities often are obtained with high-contrast optotypes. Using Variable-Contrast Visual Acuity Charts (VCVAC), we measured visual acuities of 40 eyes of 24 normal subjects (visual acuity greater than or equal to 1.0) aged 41 to 72 years, and 40 eyes of 28 cataract patients (visual acuity greater than or equal to 0.6) aged 44 to 81 years. The VCVAC consists of 4 different charts (1-4). The contrast is 90% in charts 1 and 4, 15% in chart 2 and 2.5% in chart 3. Chart 4 is the reverse polarity of chart 1. The decrease of visual acuity compared with the high-contrast chart (chart 1) was larger in the cataract group with both in the 15% contrast (0.52 vs. 0.71 octave) and the 2.5% contrast (1.21 vs. 1.75 octaves). In cataract group, 23/40 eyes (57.5%) showed better visual acuity with chart 4 than that of chart 1. In addition to high-contrast optotypes, acuity measurements using intermediate- to low-contrast optotypes, combined with the reverse polarity chart, seem effective in analyzing the visual disabilities caused by early cataract.