Visual changes in patients with early type 2 diabetes mellitus without diabetic retinopathy due to possible subclinical ischemia

Abstract

AbstractPurposeTo assess visual changes in patients suffering from early type 2 diabetes mellitus (DM2) with good metabolic control and without diabetic retinopathy as a possible implication of subclinical ischemia.MethodSixty patients with early DM2 with good metabolic control and without diabetic retinopathy and sixty age and sex‐matched healthy controls were recruited for the study. Only one eye per subject was randomly selected and included. Psychophysics tests were performed as visual acuity (VA) by ETDRS charts, colour vision using the Farnsworth and L’Anthony D15 desaturated colour tests, contrast sensitivity vision (CSV) using Pelli Robson chart and CSV 1000E test and visual field with the automated Easyfield perimeter. Systemic parameters such as the presence or absence of vascular complications and the HbA1c levels were recorded, as well as the disease duration.ResultsPatients with DM2 showed worse VA at low contrast level (2.5%, p = 0.002; 1.25%, p = 0.007), worse CSV at high spatial frequencies (12 cpd, p = 0.007; 18 cpd, p = 0.011) and worse colour vision (Farnsworth, p = 0.006; Lanthony, p < 0.001) recordings compared to the control group. However, visual field parameters were similar in both groups. Patients with more than 10 years of disease duration obtained lower results with the ETDRS test, and those ones with systemic vascular complications got worse results in CSV and colour vision tests (CSV 18 cpd, p = 0.024; Lanthony test, p = 0.014). There were no significant differences between patients with HbA1c levels higher versus lower than 7%.ConclusionsPatients with early DM2, with good metabolic control and no diabetic retinopathy showed visual dysfunction compatible with retinal neurodegeneration. Subclinical ischemia could contribute to neuronal damage, before than the evident vascular changes appear.