Influence of retinopathy on the achromatic and chromatic vision of patients with type 2 diabetes

Abstract

BackgroundLuminance contrast sensitivity and colour vision are considered to have great predictive value in the evaluation of type 2 diabetic retinopathy. However, these two visual characteristics have seldom been investigated in the same group of patients. In the present study we measured contrast sensitivity and colour vision in a group of patients with type 2 diabetes and correlated the results with estimates of common metabolic markers for the disease. A subgroup of the patients had no clinical signs of retinopathy.MethodsThe vision of 27 patients (n = 50 eyes) with type 2 diabetes, with retinopathy (n = 20 eyes), or without retinopathy (n = 30 eyes) were evaluated using two psychophysical tests, the Farnsworth–Munsell 100 hue test (FM 100), and measurements of the luminance contrast sensitivity at 11 spatial frequencies. The results were compared with measurements obtained from an age-matched control group (n = 32), and were correlated with the level of glycated haemoglobin, glycaemic level, and time of disease onset. Signs of retinopathy were identified during the ophthalmological examinations.ResultsContrast sensitivity and colour vision impairments were present at different levels in diabetes patients. Eyes with retinopathy showed more severe vision loss than eyes without retinopathy. The FM 100 test was more sensitive for separation of patients from controls. Colour vision loss had no colour axes preference. The contrast sensitivity test appeared to have some advantage in differentiating patients with retinopathy from patients without retinopathy.ConclusionsBoth methods can be useful to follow the visual function of diabetic patients and should be used together to discriminate patients from controls, as well as to identify early signs of retinal damage.

Factors associated with impaired color vision without retinopathy amongst people with type 2 diabetes mellitus: a cross-sectional study

“…Previous studies by Andrade et al, Feitosa-Santana C et al, and Sun TS and Zhang MN showed that ICV could develop in the early stage of T2DM but did not specify the minimal period for the development of color vision deficiency [2–4]. The results of this study suggest that the risk of DM increases for each additional year after the onset of T2DM.…”

The potential role of subclinical ischaemia in the visual dysfunction of patients with type 2 Diabetes Mellitus without diabetic retinopathy

“…In our study, patients with type 2 DM without diabetic retinopathy presented altered CSV only for high spatial frequencies (12 and 18 cpd). These results support previous findings, where loss of contrast sensitivity in type 2 diabetics who do not have diabetic retinopathy was hardly observed [5,14,16]. However, other researchers have found changes affecting CSV in all frequencies in patients with DM2 and no retinopathy [15,17].…”

“…Thus, the evaluation of CSV in different spatial frequencies is of great importance in these patients. It appears that, in the presence of clinical diabetic retinopathy, a decrease in contrast sensitivity is present [5,14], which may be independent of the visual acuity affectation [5,15].…”

“…Our patients presented worse BCVA at low contrast levels and worse CSV at high spatial frequencies. There are different driving paths for different frequencies in the processing of visual information and it is not known which paths are affected the most in DM [14]. Thus, the evaluation of CSV in different spatial frequencies is of great importance in these patients.…”

Functional outcome of macular edema in different retinal disorders

“…Early retinal changes may manifest in subtly altered visual functions such as color discrimination, which may appear before any visual acuity deterioration or clinically apparent retinopathy (Andrade et al, 2014). Patients can maintain good visual acuity for many years and are commonly unaware of any retinal damage or deterioration in vision (Andrade et al, 2014).…”