Sun Tang-sheng, Zhang Mao-nian
Department of Ophthalmology, 476 Clinical Department of Fuzhou General Hospital, Nanjing Military Region, Fuzhou 350002, China.
Zhonghua Yan Ke Za Zhi. 2012 Jan;48(1):41-6.
To explore the change of contrast sensitivity (CS) in diabetic patients without diabetic retinopathy.
It was a case-control study. We screened and tested 52 type 2 diabetic patients (89 eyes) and 47 healthy persons (68 eyes). OPTEC 6500 contrast sensitivity tester was used to examine near and distance CS values on 1.5, 3.0, 6.0, 12.0, 18.0 cycles/degree (c/d) respectively. We kept strict inclusion criteria on subjects, no retinopathy was found and best corrected vision acuity was above 1.0. The difference of CS values between these two groups was investigated, and the influence of gender, age, duration of diabetic mellitus and application time of insulin on CS values, respectively. T-test or u-test was used to compare the means of CS values between these two groups, near and distance CS values in each group. Simple linear correlation and multiple regression analysis were used to analyze the single factor and multiple factors correlation between CS values and age, duration, gender, and application time of insulin, respectively.
The maximum CS values in both distance and near were 112.67 ± 43.97, 85.85 ± 41.83 and 83.68 ± 35.91, 55.20 ± 24.14, both appeared in 6.0 c/d. The minimum CS values in both distance and near were 26.19 ± 17.69, 12.69 ± 7.09 and 18.68 ± 11.81, 8.22 ± 5.68, respectively, both appeared in 18.0 c/d. Distance and near CS values in diabetic group and control group had very significant differences at these five spatial frequencies (From 1.5 to 18.0 c/d, the test values on distance, t = 3.11, 3.38, 2.77, 3.48, 3.86; P < 0.05; the test values on near, u = 3.70, 3.22; t' = 3.69, 3.88, 4.25; P < 0.05). Abnormal rate in diabetic group on high, medium, low and all frequencies were higher than control group, regardless of distance or near CS values (in near χ(2) = 11.86, 8.17, 9.14, 5.81; P < 0.05; on 4 combinations in distance χ(2) = 13.27, 6.70, 4.01, 4.50; P < 0.05). In diabetic group, gender related with 3.0 and 6.0 c/d CS values on near-distance (r = 0.26, 0.28; P < 0.05); age related with high-frequencies on near (r = -0.45, -0.28; P < 0.05); duration of diabetic mellitus related with high-frequencies on near (r = -0.25, -0.39; P < 0.05), and related with medium, high frequencies on distance (r = -0.26, -0.28, -0.30, -0.34; P < 0.05); application time of insulin related with high-frequencies on distance (r = -0.30, -0.31; P < 0.05).
There exists important sense of CS value on showing visual function changes accurately in early-stage of diabetes mellitus. The high frequencies on distance is the sensitive index in vision impairment. Duration of diabetes closely relates with changes of retinal function ultimately, can be classified as the most important risk factor of CS values decline in early-stage diabetic patients.
探讨无糖尿病视网膜病变的糖尿病患者对比敏感度（CS）的变化。
这是一项病例对照研究。我们筛选并测试了52例2型糖尿病患者（89只眼）和47名健康人（68只眼）。使用OPTEC 6500对比敏感度测试仪分别检测1.5、3.0、6.0、12.0、18.0周期/度（c/d）的近距和远距CS值。我们对受试者严格设定纳入标准，未发现视网膜病变且最佳矫正视力高于1.0。研究两组之间CS值的差异，以及性别、年龄、糖尿病病程和胰岛素应用时间分别对CS值的影响。采用t检验或u检验比较两组之间、每组近距和远距CS值的均值。分别采用简单线性相关和多元回归分析分析CS值与年龄、病程、性别和胰岛素应用时间之间的单因素和多因素相关性。
远距和近距的最大CS值分别为112.67±43.97、85.85±41.83和83.68±35.91、55.20±24.14，均出现在6.0 c/d。远距和近距的最小CS值分别为26.19±17.69、12.69±7.09和18.68±11.81、8.22±5.68，均出现在18.0 c/d。糖尿病组和对照组在这五个空间频率下的远距和近距CS值有非常显著差异（从1.5至18.0 c/d，远距测试值，t = 3.11、3.38、2.77、3.48、3.86；P < 0.05；近距测试值，u = 3.70、3.22；t' = 3.69、3.88、4.25；P < 0.05）。无论远距还是近距CS值，糖尿病组在高、中、低频率及所有频率下的异常率均高于对照组（近距χ(2)=11.86、8.17、9.14、5.81；P < 0.05；远距4种组合χ(2)=13.27、6.70、4.01、4.50；P < 0.05）。在糖尿病组中，性别与近远距3.0和6.0 c/d CS值相关（r = 0.26、0.28；P < 0.05）；年龄与近距高频相关（r = -0.45、-0.28；P < 0.05）；糖尿病病程与近距高频相关（r = -0.25、-0.39；P < 0.05），且与远距中高频相关（r = -0.26、-0.28、-0.30、-0.34；P < 0.05）；胰岛素应用时间与远距高频相关（r = -0.30、-0.31；P < 0.05）。
CS值对于准确显示糖尿病早期视觉功能变化具有重要意义。远距高频是视力损害的敏感指标。糖尿病病程最终与视网膜功能变化密切相关，可被列为早期糖尿病患者CS值下降的最重要危险因素。
