Abstract
Purpose Alterations in visual field (VF) and retinal nerve fiber layer (RNFL) thickness were reported in diabetics. Little is known however about the extent to which VF and RNFL changes are affected and their correlations. The purpose was to assess the RNFL thickness and its correlation with VF parameters in type 2 diabetics without retinopathy with well controlled glucose level and good standard visual acuity. Methods A total of 28 controls and 16 type 2 diabetics without retinopathy were recruited. VF was assessed with the frequency doubling technology (FDT) perimeter using the full threshold C-20 program. The RNFL thickness was acquired by the optical coherence tomography 200 × 200 optic disc cube scanning protocol. Forward stepwise multiple linear regression analysis was applied to rule out the independent association of the RNFL thickness with the FDT parameters. Results Compared to the controls, the diabetics showed a trend of decreased RNFL thickness but was not significant, lower sensitivities for some VF locations, no difference in the mean deviation, and worse mean pattern standard deviation (PSD) (3.89 ± 0.36 vs. 3.47 ± 0.58 dB, p < 0.05). The RNFL thickness was significantly negatively correlated with PSD (r = -0.6, p < 0.05). Conclusions Apparent VF changes precede RNFL thickness thinning in type 2 diabetics without retinopathy. Also, the RNFL thickness shows a negative correlation with the PSD of the FDT parameter.