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).
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 Â± 3.03 vs -2.94 Â± 2.21; p=0.09), PSD (3.08 Â± 1.28 vs 2.69 Â± 0.47; p=0.23) and average peripapillary RNFL thickness (98.47 Â± 6.89 vs 98.72 Â± 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.