title: Influence of retinopathy on the achromatic and chromatic vision of patients with type 2 diabetes.
abstract: BACKGROUND
  Luminance 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.
  
  
  METHODS
  The 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.
  
  
  RESULTS
  Contrast 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.
  
  
  CONCLUSIONS
  Both 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.
authors.forename: Luciana Cristina O
authors.initials: LC
authors.lastname: Andrade
authors.forename: Givago S
authors.initials: GS
authors.lastname: Souza
authors.forename: Eliza Maria C B
authors.initials: EM
authors.lastname: Lacerda
authors.forename: Maira Tst
authors.initials: MT
authors.lastname: Nazima
authors.forename: Anderson R
authors.initials: AR
authors.lastname: Rodrigues
authors.forename: Liudmila M
authors.initials: LM
authors.lastname: Otero
authors.forename: Francineide Ps
authors.initials: FP
authors.lastname: Pena
authors.forename: Luiz Carlos L
authors.initials: LC
authors.lastname: Silveira
authors.affiliation: Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Amapá, 68903-419 Macapá, Amapá, Brazil. mitcortes@unifap.br.
authors.forename: Maria Izabel T
authors.initials: MI
authors.lastname: Côrtes
mesh_terms: D055253:Color Vision / Q000502:physiology*; D003117:Color Vision Defects / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D015350:Contrast Sensitivity; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014792:Visual Acuity