Bittner Ava K, Jeter Pamela, Dagnelie Gislin
Lions Vision Center, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland 21205-2020, USA.
Optom Vis Sci. 2011 Oct;88(10):1153-63. doi: 10.1097/OPX.0b013e3182271638.
To evaluate the reliability and validity of grating visual acuity (VA) and contrast sensitivity (CS) tests, which could be useful outcome measures to assess changes in severely reduced vision.
The Grating Acuity Test (GAT) and Grating Contrast Sensitivity (GCS) tests, which involve the detection of grating orientation in a four-Alternative Forced Choice paradigm on a liquid crystal display screen, were compared with the well-validated Early Treatment of Diabetic Retinopathy Study (ETDRS) and Pelli-Robson (PR) charts. Grating tests were repeated two or three times within-visit, across three or four sessions, in 20 legally blind subjects: 8 with retinitis pigmentosa (RP) (16 eyes) and 12 with other retinal diseases (OR) (16 eyes).
VA determined by ETDRS and GAT was in good agreement and scaled very similarly, as shown by regression of the within-session difference between the two measures against their mean [RP group: slope (m) = 0.11; 95% confidence interval [CI]: -0.06, 0.29; p = 0.21; OR group: m = -0.07; 95% CI: 0.33, 0.20; p = 0.62]. On average, higher logCS levels were obtained using the GCS than the PR in both groups. The two CS measures scaled similarly in the RP group (m = 0.07; 95% CI: -0.09, 0.22; p = 0.39) but not in the OR group (m = 0.41; 95% CI: 0.12, 0.70; p = 0.005). The within- and between-visit 95% coefficient of repeatability (CR.95) were 0.11 to 0.17 log units for the ETDRS charts and GAT in both groups and 0.14 to 0.15 log units for the PR and GCS in the RP group, whereas the OR group demonstrated more variability in CS. Between-visit CR.95 did not significantly change with mean VA or CS for the ETDRS, PR, or GCS tests, but RP patients' CR.95 on the GAT increased significantly with decreasing VA. Floor effects occurred for some RP eyes with ETDRS and PR charts but not with the GAT and GCS.
Computer-driven grating tests appear to be reliable, capable of evaluating vision that may fall outside of the range of standard clinical tests and may be useful during clinical trials for advanced eye disease.
评估光栅视力（VA）和对比敏感度（CS）测试的可靠性和有效性，这两种测试可能是评估严重视力下降变化的有用结果指标。
将光栅视力测试（GAT）和光栅对比敏感度（GCS）测试（这两项测试涉及在液晶显示屏上的四选一强制选择范式中检测光栅方向）与经过充分验证的糖尿病视网膜病变早期治疗研究（ETDRS）图表和佩利 - 罗布森（PR）图表进行比较。在20名法定盲人受试者中，光栅测试在每次就诊时重复进行两到三次，共进行三到四个疗程，其中8名患有色素性视网膜炎（RP）（16只眼），12名患有其他视网膜疾病（OR）（16只眼）。
ETDRS和GAT测定的视力一致性良好且缩放方式非常相似，这通过两种测量方法的疗程内差异相对于其平均值的回归分析得以体现[RP组：斜率（m）= 0.11；95%置信区间[CI]：-0.06，0.29；p = 0.21；OR组：m = -0.07；95% CI：0.33，0.20；p = 0.62]。平均而言，两组中使用GCS获得的对数CS水平均高于PR。在RP组中，两种CS测量方法的缩放方式相似（m = 0.07；95% CI：-0.09，0.22；p = 0.39），但在OR组中并非如此（m = 0.41；95% CI：0.12，0.70；p = 0.005）。两组中ETDRS图表和GAT的就诊内及就诊间95%重复性系数（CR.95）为0.11至0.17对数单位，RP组中PR和GCS的为0.14至0.15对数单位，而OR组在CS方面表现出更大的变异性。对于ETDRS、PR或GCS测试，就诊间CR.95不会随平均VA或CS显著变化，但RP患者在GAT上的CR.95会随着VA降低而显著增加。一些RP眼使用ETDRS和PR图表时出现了下限效应，但使用GAT和GCS时未出现。
计算机驱动的光栅测试似乎是可靠的，能够评估可能超出标准临床测试范围的视力，并且在晚期眼病的临床试验中可能有用。
