AIM: To investigate the effect of Ginkgo leaf extract on the neural protection of diabetic retinopathy(DR).

METHODS: Ninety-eight patients(196 eyes)with type 2 DR were collected from January 2011 to December 2013 in our hospital. According to the visiting sequence, they were randomly divided into control group and treatment group. The control group was given oral hypoglycemic drugs and/or insulin therapy. The treatment group was given Ginkgo leaf extract and oral hypoglycemic drugs and/or insulin therapy. The fasting blood glucose, glycosylated hemoglobin, OCT and electrophysiology were performed before treatment, 3, 6, 9 and 12mo after treatment. The follow-up time was 12mo.

RESULTS: The glucose and glycosylated hemoglobin in the control group were similar to those of the treatment group. The differences between two groups had no statistical significance(before glucose treatment: t=1.632, P=0.106; 3mo after treatment: t=0.096, P=0.924; 6mo after treatment: t=1.381, P=0.171; 9mo after treatment: t=1.459, P=0.148; 12mo after treatment: t=0.358, P=0.721. before glycosylated hemoglobin treatment: t=0.512, P=0.610; 3mo after treatment: t=0.020, P=0.984; 6mo after treatment: t=0.252, P=0.802; 9mo after treatment: t=0.852, P=0.397; 12mo after treatment: t=0.281, P=0.779). The amplitude of Ops wave in the control group was lower than that in the treatment group. The differences of 6, 9 and 12mo between groups were statistically significant(6mo t=2.454, P=0.015; 9mo t=3.415, P=0.001; 12mo t=3.573, P<0.01). The latency of Ops wave in the control group was longer than that in the treatment group. The differences of 9 and 12mo between groups were statistically significant(9mo t=2.708, P=0.007; 12mo t=3.005, P=0.003). The amplitude of P₁₀₀ wave in the control group was lower than that in the treatment group. The differences of 6, 9 and 12mo between groups were statistically significant(6mo t=3.314, P=0.001; 9mo t=5.542, P<0.01; 12mo t=5.986, P<0.01). The latency of P₁₀₀ wave in the control group was longer than that in the treatment group. The differences of 3, 6, 9 and 12mo between groups were statistically significant(3mo t=2.335, P=0.021; 6mo t=2.777, P=0.006; 9mo t=5.350, P<0.01; 12mo t=8.440, P<0.01). The retinal nerve fiber layer thickness in the control group was thicker than that in the treatment group. The differences of 3, 6, 9 and 12mo between groups were statistically significant(3mo t=5.146, P<0.01; 6mo t=10.484, P<0.01; 9mo t=10.528, P <0.01; 12mo t=18.378, P<0.01).

CONCLUSION: Ginkgo leaf extract can reduce macular edema, improve the retinal ganglion cell function in patients with DR.