Visual Neuroscience



CLINICAL PSYCHOPHYSICS

Color space distortions in patients with type 2 diabetes mellitus


CLAUDIA  FEITOSA-SANTANA  a1 a2 c1 , NESTOR N.  OIWA  a1 a3 , GALINA V.  PARAMEI  a4 , DAVID  BIMLER  a5 , MARCELO F.  COSTA  a1 a2 , MARCOS  LAGO  a1 a2 , MAURO  NISHI  a6 and DORA F.  VENTURA  a1 a2
a1 Depto. Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, São Paulo, Brasil
a2 Núcleo de Neurociências e Comportamento, Universidade de São Paulo, São Paulo, Brasil
a3 Depto. F ísica Geral, Instituto de F ísica, Universidade de São Paulo, São Paulo, Brasil
a4 Institute of Psychology, Darmstadt University of Technology, Darmstadt, Germany
a5 Department of Health and Human Development, Massey University, Palmerston North, New Zealand
a6 Hospital Universitário, Universidade de São Paulo, São Paulo, Brasil

Article author query
feitosa-santana c   [Google Scholar] 
oiwa nn   [Google Scholar] 
paramei gv   [Google Scholar] 
bimler d   [Google Scholar] 
costa mf   [Google Scholar] 
lago m   [Google Scholar] 
nishi m   [Google Scholar] 
ventura df   [Google Scholar] 
 

Abstract

Color vision impairment was examined in patients with type 2 diabetes mellitus (DM2) without retinopathy. We assessed the type and degree of distortions of individual color spaces. DM2 patients (n = 32), and age-matched controls (n = 20) were tested using the Farnsworth D-15 and the Lanthony D-15d tests. In addition, subsets of caps from both tests were employed in a triadic procedure (Bimler & Kirkland, 2004). Matrices of inter-cap subjective dissimilarities were estimated from each subject's “odd-one-out” choices, and processed using non-metric multidimensional scaling. Two-dimensional color spaces, individual and group (DM2 patients; controls), were reconstructed, with the axes interpreted as the R/G and B/Y perceptual opponent systems. Compared to controls, patient results were not significant for the D-15 and D-15d. In contrast, in the triadic procedure the residual distances were significantly different compared to controls: right eye, P = 0.021, and left eye, P = 0.022. Color space configurations for the DM2 patients were compressed along the B/Y and R/G dimensions. The present findings agree with earlier studies demonstrating diffuse losses in early stages of DM2. The proposed method of testing uses color spaces to represent discrimination and provides more differentiated quantitative diagnosis, which may be interpreted as the perceptual color system affected. In addition, it enables the detection of very mild color vision impairment that is not captured by the D-15d test. Along with fundoscopy, individual color spaces may serve for monitoring early functional changes and thereby to support a treatment strategy.

(Received September 5 2005)
(Accepted May 4 2006)


Key Words: Color vision deficiency; Diabetes mellitus type 2; Lanthony D-15d; Multidimensional scaling; Color space.

Correspondence:
c1 Address correspondence and reprint requests to: Claudia Feitosa Santana, Depto. Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, Av. Professor Mello Moraes, 1721 Bloco A Sala D-9-05508-900 São Paulo, SP, Brasil. E-mail: claudia@feitosa-santana.com