Schulze-Bonsel Kilian, Feltgen Nicolas, Burau Hermann, Hansen Lutz, Bach Michael
Department of Ophthalmology, University of Freiburg, Freiburg, Germany.
Invest Ophthalmol Vis Sci. 2006 Mar;47(3):1236-40. doi: 10.1167/iovs.05-0981.
The visual acuity (VA) of patients with very low vision is classified using the semiquantitative scale "counting fingers" (CF), "hand motion" (HM), "light perception" (LP), and "no light perception." More quantitative measures would be desirable, especially for clinical studies. The results of clinical VA measurements, Early Treatment Diabetic Retinopathy Study (ETDRS) charts, and the Freiburg Visual Acuity Test (FrACT) were compared. The FrACT is a computerized visual acuity test that can present very large Landolt C optotypes when necessary.
Examined were 100 eyes of 100 patients with various eye diseases (e.g., diabetic retinopathy, ARMD), covering a range of VAs from LP to decimal 0.32. The FrACT optotypes were presented on a 17-inch LCD monitor with random orientation. After extensive training, two ETDRS and FrACT measurements were obtained. The testing distance was 50 or 100 cm.
ETDRS and FrACT coincided closely for VA > or = 0.02 (n = 80). ETDRS measures were successfully obtainable down to CF (at 30 cm; test-retest averaged over all patients, coefficient of variation CV = 9% +/- 8%), and FrACT provided reproducible measurements down to HM (test-retest CV(FrACT) =12% +/- 11%). For CF (n = 6), both ETDRS and FrACT resulted in a mean VA of 0.014 +/- 0.003 (range, 0.01-0.02). The VA results of FrACT for HM (n = 12) were 0.005 +/- 0.002 (range, 0.003-0.009); the individual values were highly reproducible. No results were obtainable for LP (n = 2).
The three acuity procedures concur above a VA of 0.02. The results suggest that the category CF at 30 cm can be replaced by 0.014, using ETDRS or FrACT. Using FrACT, one can even reproducibly quantify VA in the HM-range, yielding a mean VA of 0.005.
视力极低的患者的视力（VA）使用半定量量表“数手指”（CF）、“手动”（HM）、“光感”（LP）和“无光感”进行分类。更具定量性的测量方法会更可取，尤其是对于临床研究。对临床视力测量结果、早期糖尿病视网膜病变研究（ETDRS）视力表和弗莱堡视力测试（FrACT）的结果进行了比较。FrACT是一种计算机化视力测试，必要时可呈现非常大的兰道环（Landolt C）视标。
对100例患有各种眼部疾病（如糖尿病视网膜病变、年龄相关性黄斑变性）的患者的100只眼睛进行了检查，涵盖了从LP到小数0.32的一系列视力。FrACT视标在17英寸液晶显示器上以随机方向呈现。经过广泛训练后，获得了两次ETDRS和FrACT测量结果。测试距离为50或100厘米。
对于视力≥0.02（n = 80），ETDRS和FrACT结果非常接近。ETDRS测量结果在CF（30厘米处）时仍可成功获得（所有患者的重测平均值，变异系数CV=9%±8%），FrACT在HM范围内提供了可重复的测量结果（重测CV(FrACT)=12%±11%）。对于CF（n = 6），ETDRS和FrACT得出的平均视力均为0.014±0.003（范围，0.01 - 0.
