title: Early loss of blue-sensitive color vision in patients with type I diabetes.
abstract: Existing methods for early detection of ocular injury from diabetes have serious limitations. We describe a new method, measuring visual flicker discrimination of the blue-sensitive mechanism of vision. This method is noninvasive, quantitative, and capable of distinguishing two types of impairment. Blue-flicker discrimination was measured in 10 adults with type I (insulin-dependent) diabetes for less than 5 yr. Although no evidence of diabetic changes was detected by careful ophthalmic examination by an experienced ophthalmologist, 12 of 19 eyes (63%) had flicker discrimination scores considered abnormal in comparison with those of a control group, and 8 of 10 subjects (80%) had at least 1 eye with abnormal performance. In all but 2 abnormal eyes the deficit of blue-flicker discrimination was of the "absorptive" type, suggesting increased absorbance or scattering of blue light in the optical media. These data show that a functional impairment of vision can be measured very early in the course of type I diabetes, before visible retinopathy is present, and suggest this test procedure may have both investigative and clinical applications.
mesh_terms: D000328:Adult; D003118:Color Perception; D003117:Color Vision Defects / Q000209:etiology / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D014792:Visual Acuity