The positive culture ratio was 33.3% in proliferative diabetic retinopathy (PDR) patients and 55.6% in patients using insulin; however, neither group showed a significant difference from the control group in the frequency of positive cultures (chi-square=0.99, p=0.609 and chi-square=2.73, p=0.098, respectively). The gene discussed is INS; the disease is proliferative diabetic retinopathy.