Retinal Sensitivity in Patients with Type I Diabetes without Retinopathy or with Minor Retinal Changes

Objective: To evaluate the ability of short-wavelength automated perimetry (SWAP) for the detection of visual impairment in patients with type I diabetes without retinopathy or with minor retinal vascular changes. Design: Comparative cross-sectional study. Participants: 30 eyes of 30 healthy subjects and 73 eyes of 73 patients with type I diabetes mellitus were studied. Methods: Ophthalmic examination of diabetic patients showed no retinopathy or minimal changes (less than 5 microaneurisms in each eye) with no previous laser treatment. All patients were examined by means of the SWAP 24-2 strategy. Mean Deviation (MD) and Pattern Standard Deviation (PSD) were compared between both groups. Results: There were differences in the clusters of altered points between both groups (p = 0.004). SWAP MD was lower in the diabetic group than in the controls (-2.89 dB vs. -0.20 dB, p < 0.001). SWAP PSD also differed between both groups (2.50 dB in control group, 3.12 dB in the diabetic group, p = 0.003). In the diabetic group, mean period from the onset of diabetes was 12.6 +/- 6.7 years and minimal vascular changes were observed in the retina of 18 eyes (24.7 %), while 55 had no lesions (75.3 %). No differences in SWAP changes were found between patients without and with minimal diabetic retinopathy. Conclusions: Retinal sensitivity assessed by SWAP is depressed in patients with type I diabetes regardless of the presence of retinal vascular changes.