Short Wavelength Automated Perimetry and Peripapillary Retinal Nerve Fiber Layer in Early Diabetes

Abstract

Objective: To investigate the significance of short wavelength automated perimetry (SWAP) in detecting retinal functional impairment in early diabetic patients without retinopathy and with mild non-proliferative diabetic retinopathy (NPDR).

Materials and Methods: This is a prospective, cross-sectional study of 37 eyes of early diabetics which were divided into 2 groups: no DR with 18 subjects and mild NPDR with 19. All subjects underwent HBA1C, SWAP, peripapillary RNFL thickness measurement and fundus photo. Visual field indices: MD and PSD as well as average RNFL thickness were compared among the 2 groups. Correlation of MD with RNFL thickness and HBA1C were also analyzed.

Results: There was no statistically significant difference in the MD (-4.46 ± 3.03 vs -2.94 ± 2.21; p=0.09), PSD (3.08 ± 1.28 vs 2.69 ± 0.47; p=0.23) and average peripapillary RNFL thickness (98.47 ± 6.89 vs 98.72 ± 11.01; p=0.93) among early diabetics with mild NPDR and no signs of DR. There is no correlation between MD and RNFL thickness in the no DR group (R² =0.017) and the mild DR group (R² =0.000). There was a weak correlation between MD and HBA1C in the no DR group (R² =0.137), while no correlation was seen in the mild NPDR group (R² =0.000).

Conclusion: SWAP does not appear to be a sensitive measure of worsening retinopathy in older individuals with early diabetes. The usefulness of SWAP and peripapillary RNFL thickness in the early stages of retinopathy are inconclusive.