Evaluation of diabetic retinopathy by automated static perimetry

Decibel values of threshold sensitivity depression of the retina were evaluated in 69 eyes with NIDDM using the Humphrey automated static perimeter. The eyes were classified into three groups: group I (GI) consisting of 32 eyes with no retinopathy or with stages 1 and 2 of simple diabetic retinopathy, group II (GII) consisting of 21 eyes with stage 3 of simple retinopathy or pre-proliferative retinopathy and group III (GIII) consisting of 16 eyes treated by panretinal photocoagulation using an argon laser. The average age in each group was 60 years and all eyes had a visual acuity of over 0.6. As controls, 16 normal eyes were examined. In comparison with the values of the control, the mean of the sum of decibel threshold sensitivity in the macular retina significantly decreased by 5% in GI, 7.8% in GII, and 24.3% in GIII. It was found that the mean of the sum of decibels in the central retina decreased by 8.2% in GI and 15.5% in GII. The sum of decibels in the mid-peripheral retina showed a decrease of 11.4% in GI and 27.5% in GII. In addition, the decibel values of threshold sensitivity of the lower half of the retina tended to decrease more easily than those of the upper half of the retina in the parafoveal and the macular areas. It was also suggested that decibel values of threshold sensitivity of the retina may decrease shortly after PRP in the paramacular area (located about 10 degrees from the fovea) but not in the foveal area.