Neurodegenerative differences in the retinas of male and female patients with type 2 diabetes

Abstract

Purpose: The purpose of our study is to determine whether neuroretinal function, measured by the multifocal electroretinogram, differs between males and females with type 2 diabetes and no retinopathy.

Methods: This study included 70 eyes from 70 adult subjects (14 control males, 22 control females, 16 males with type 2 diabetes, and 18 females with type 2 diabetes). A template-scaling technique was used to obtain first-order P1 implicit times and N1-P1 amplitudes from photopic multifocal electroretinograms within the central 45 degrees.

Results: The males with type 2 diabetes were significantly more abnormal than their female counterparts in two separate analyses of local neuroretinal function. First, the total number of retinal locations with an abnormally delayed implicit time (z score ≥ 2) was higher (P < 0.001) in the diabetic males (482 locations = 29.2%) compared to the diabetic females (298 locations = 16.1%). Second, in the response topographies that consisted of 103 means of local implicit times for each group, the diabetic males were significantly delayed (P < 0.025) at 23 corresponding positions (22.3%) compared to the diabetic females. At the same time, no corresponding stimulus locations were significantly delayed in the diabetic females compared to the diabetic males.

Conclusions: Neuroretinal function is more abnormal in males than in females for adults with type 2 diabetes and no retinopathy. These results suggest that, relative to males, females may have some protection from, or resistance to, neurodegenerative changes that precede the development of background retinopathy in type 2 diabetes.

Figure 1.

Waveform showing location of N1 trough and P1 peak.

Figure 2.

Retinal view in left-eye format showing the occurrence of implicit time abnormalities (z score ≥ 2) at each location in the stimulus array for the diabetic males (left) and the diabetic females (right).

Figure 3.

Average whole eye implicit times. Bars indicate 1 SE. The males with type 2 diabetes (29.7 ± 0.3 ms) had significantly longer latencies (*P = 0.011) than the control males (28.8 ± 0.2 ms). The implicit times of the females with type 2 diabetes (29.1 ± 0.2 ms) were similar to the control females (28.6 ± 0.2 ms).

Figure 4.

Amplitudes across whole eyes. Bars indicate 1 SE. Amplitudes were not significantly different among the groups. The values for the control males, males with type 2 diabetes, control females, and females with type 2 diabetes were 203.7 ± 11.1, 198.6 ± 15.1, 198.7 ± 12.6, and 194.2 ± 11.9 nV, respectively.