[Reliability of evaluating grade of diabetic retinopathy]

The inter-rater and intra-rater reliability of stage-evaluation for diabetic retinopathy using Fukuda's classification was assessed by the kappa coefficient. The raters consisted of 16 ophthalmologists in 3 institutions. The kappa coefficient was calculated to evaluate the inter-rater reliability. Evaluation was performed twice. The value of the kappa coefficient for the first evaluation was 0.18 and that for the second time evaluation was 0.081. The kappa coefficient for evaluation of the change of retinopathy grade was 0.24. The agreement of evaluation using color fundus photographs was higher than that using both color fundus photographs and fluorescein angiograms. The agreement of the evaluation of retinopathy grades did not correlate with periods of experience as ophthalmologists. The intra-rater agreement of the evaluation of retinopathy grades was 60-70%. These results suggested that the reliability of the evaluation of retinopathy grades was not high among ophthalmologists and that standardization in clinical investigation of diabetic retinopathy was necessary using fundus photographs and fluorescein angiograms.