Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Tel-Aviv University, 52621, Tel-Aviv, Israel.
Graefes Arch Clin Exp Ophthalmol. 2010 Dec;248(12):1699-703. doi: 10.1007/s00417-010-1413-y. Epub 2010 May 25.
Contrast sensitivity (CS) has been studied extensively to determine its effectiveness as a test for diagnosing early and advanced diabetic retinopathy. Various techniques have been adopted to measure CS, and most of them reported a significant difference between diabetic and normal eyes. Our purpose is to demonstrate differences in foveal CS between diabetic patients without retinopathy and healthy subjects under mesopic and photopic conditions, using a simple, rapid computerized test.
Seventeen eyes of nine patients with type 2 diabetes without diabetic retinopathy were included. Fourteen eyes of seven non-diabetic patients served as controls. All the patients underwent a careful ophthalmologic examination, including ETDRS chart visual acuity, color photographs, and optical coherence tomography (OCT). Patients with any ocular disease were excluded. All eyes had a visual acuity of 20/25 or better, a normal eye examination and optical coherence tomography (OCT). Photopic and mesopic contrast sensitivity was tested using a computerized psychophysical static method involving four forced-choice procedures. The targets were Gabor patches with spatial frequencies of 3-12 cycles per degree (cpd). The mesopic testing was conducted in a completely darkened room; the monitor was covered with a neutral density filter, allowing luminance of only 0.9 cd/m(2).
The average age was similar: 59.1 ± 5.3 years in the diabetic group vs 61.4 ± 3.2 years in the control group. The average duration of diabetes was 16 years (range 6-26). The average visual acuity was 0.04 ± 0.01 logMAR and 0.01 ± 0.01 logMAR in the diabetic and control groups respectively. Photopic foveal CS was similar in both groups. Significantly lower CS was found in diabetic patients under mesopic conditions at a spatial frequency of 3 (p < 0.008). At higher spatial frequencies, the mesopic contrast sensitivity was very low in both groups and without a significant difference.
Mesopic foveal CS is impaired in diabetic patients despite good visual acuity, a normal fundus examination and normal OCT. Early central visual function impairment may occur in diabetic patients before the appearance of retinopathy.
对比敏感度 (CS) 已被广泛研究，以确定其作为诊断早期和晚期糖尿病视网膜病变的测试的有效性。已经采用了各种技术来测量 CS，其中大多数报告了糖尿病眼与正常眼之间的显著差异。我们的目的是在中光和高光条件下，使用简单、快速的计算机化测试，证明无糖尿病视网膜病变的糖尿病患者的中央凹 CS 与健康受试者之间存在差异。
纳入了 9 名 2 型糖尿病患者的 17 只眼，这些患者无糖尿病视网膜病变。7 名非糖尿病患者的 14 只眼作为对照。所有患者均接受了详细的眼科检查，包括 ETDRS 图表视力、彩色照片和光学相干断层扫描 (OCT)。排除任何眼部疾病的患者。所有患者的视力均为 20/25 或更好，眼部检查和光学相干断层扫描 (OCT) 正常。使用涉及四个强制选择程序的计算机化心理物理静态方法测试明视和中光对比敏感度。目标是具有 3-12 个周期/度 (cpd) 空间频率的 Gabor 补丁。中光测试在完全黑暗的房间中进行；监视器用中性密度滤光片覆盖，仅允许 0.9 cd/m(2) 的亮度。
平均年龄相似：糖尿病组为 59.1 ± 5.3 岁，对照组为 61.4 ± 3.2 岁。糖尿病的平均病程为 16 年（范围 6-26 年）。平均视力分别为糖尿病组和对照组的 0.04 ± 0.01 logMAR 和 0.01 ± 0.01 logMAR。两组明视中央 CS 相似。在空间频率为 3 时，糖尿病患者在中光条件下的 CS 明显较低（p < 0.008）。在较高的空间频率下，两组的中光对比敏感度都非常低，且无显著差异。
尽管视力良好、眼底检查正常和 OCT 正常，但糖尿病患者的中光中央 CS 受损。糖尿病患者可能在出现视网膜病变之前就出现了早期中央视觉功能障碍。
