Abstract
Abstract: :
Purpose: To evaluate the color discrimination in type 2 diabetic (DM) patients by Farnsworth (D15), Lanthony (D15d) and Cambridge Color Test (CCT). Methods: The D15 and D15d tests were applied in 27 DM patients (mean=53.7 SD=10.6) and in 34 age–matched controls (mean=50.8 SD=13.5) with the specified illumination (103 lux provided by two fluorescent lamps Sylvania Octron 6500 K FO32W/65K). The CCT was performed in a subgroup of 21 DM patients and in 27 age–matched controls. We used the Trivector test, a short version used for rapid screening, and the Ellipses test which determine a MacAdam ellipse. All subjects had normal ophthalmologic examination and were tested monocularly. Results: DM results were worse for all Trivector confusion lines (protan, p=.008; deutan, p=.002; tritan, p<.001) and ellipse area (p=.032). The results for the D15 and D15d showed difference in comparison with controls, respectively, p=.022; p=.002. Moderate correlation was verified between the duration of DM and the D15 results (r= .48; p= .011) and D15d (r= .45; p= .017). A correlation between duration of DM and color vision loss was also found for the CCT results in the protan (r= .48; p= .028) and tritan (r= .60; p= .003) axes of the Trivector test and in the MacAdam ellipse area (r= .53; p= .015). Total number of patients with color vision losses was similar in the CCT (57%) and the D15d (60%). Both were correlated with the time of DM (CCT r= .70, p< .001; D15d r= .39, p= .044). Among the patients with color defect classification, the distribution of type of defect is very similar in both tests (CCT tritan= 58%, diffuse= 42%; D15d tritan= 56%, diffuse= 44%). Conclusions: About 60% of the non–retinopathic diabetic patients have color vision losses measured by the D15d and CCT. Most are tritan defects, but both the CCT and the D15d show that at least 40% of the losses may be diffuse.
Keywords: color vision • diabetes • clinical (human) or epidemiologic studies: risk factor assessment