Aim: to investigate the role of Humphrey-Matrix threshold testing in the detection of early functional retinal impairment in patients with Diabetes Mellitus type 1 (DM1) without any signs of retinal vasculopathy and to investigate the relationship between both functional and structural retinal parameters and metabolic control.
Methods: Thirty eyes of 30 DM1 patients, with no sign of retinal vasculopathy, and 30 eyes of 30 age- and sex-matched healthy subjects were enrolled in this cross-sectional clinical study. Functional testing included Humphrey-Matrix Perimetry and White-on-white Humphrey Visual Field Perimetry (HFA), while RNFL thickness was measured by Scanning Laser Polarimetry with variable corneal birefringence compensator (GDx VCC).
Results: Matrix Mean Deviation (MD) was found to be significantly reduced in DM1 patients compared to controls (-1.10±2.98, 95%CI -2.21, 0.01 vs 1.37±2.11, 95%CI 0.58, 2.16, p=0.0005). HFA MD and Pattern Standard Deviation (PSD) were significantly worse in DM1 patients compared to controls (p=0.010 and p=0.013 respectively). Among structural parameters, average peripapillary RNFL thickness was reduced in DM1 patients (p=0.006). Matrix MD and HFA MD and PSD, average peripapillary and superior Retinal Nerve Fiber Layer (RNFL) were significantly reduced in DM1 patients with HbA1c>7% compared to controls.
Conclusions: Functional and structural retinal testing by Humphrey-Matrix and GDx VCC could be useful for the identification of early retinal impairment in DM1 patients with no sign of retinal vasculopathy.