The role of Humphrey Matrix testing in the early diagnosis of retinopathy in type 1 diabetes

Aim: The aim of the study was to investigate the role of Humphrey Matrix threshold testing in the detection of early functional retinal impairment in subjects with type 1 diabetes mellitus (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 subjects with DM1, with no sign of retinal vasculopathy, and 30 eyes of 30 age- and sex-matched healthy subjects were enrolled in this crosssectional clinical study. Functional testing included Humphrey Matrix perimetry and white-on-white Humphrey visual field perimetry (HFA), while retinal nerve fibre layer (RNFL) thickness was measured by scanning laser polarimetry with variable corneal birefringence compensator (GD× VCC). Results: Matrix mean deviation (MD) was found to be significantly reduced in subjects with DM1 compared with controls (-1.10 (SD 2.98; 95% Cl -2.21 to 0.01) vs 1.37 (SD 2.11; 95% Cl 0.58 to 2.16), p = 0.0005). HFA MD and pattern standard deviation (PSD) were significantly worse in subjects with DM1 compared with controls (p = 0.010 and p = 0.013 respectively). Among structural parameters, average peripapillary RNFL thickness was reduced in DM1 subjects (p = 0.006). Matrix MD and HFA MD and PSD, and average peripapillary and superior RNFL, were significantly reduced in subjects with DM1 with HbA1c ≥7% compared with controls. Conclusions: Functional and structural retinal testing by Humphrey Matrix and GDx VCC could be useful for the identification of early retinal impairment in people with DM1 with no sign of retinal vasculopathy.