Sensitivity and specificity of a new scoring system for diabetic macular oedema detection using a confocal laser imaging system

Aim-To assess the use of the Heidelberg retina tomograph (HRT) in screening for sight threatening diabetic macular oedema in a hospital diabetic clini c, using a new subjective analysis system (SCORE). Methods-200 eyes of 100 consecutive diabetic patients attending a diabetolo gist's clinic were studied, all eyes had an acuity of 6/9 or better. All pa tients underwent clinical examination by an ophthalmologist. Using the HRT, one good scan was obtained for each eye centred on the fovea. A System for Classification and Ordering of Retinal Edema (SCORE) was developed using s ubjective assessment of the colour map and the reflectivity image. The inte robserver agreement of using this method to detect macular oedema was asses sed by two observers (ophthalmic trainees) who were familiarised with SCORE by studying standard pictures of eyes not in the study. All scans were gra ded from 0-6 and test positive cases were defined as having a SCORE value o f 0-2. The sensitivity of SCORE was assessed by pooling the data with an ad ditional 88 scans of 88 eyes in order to reduce the confidence interval of the index. Results-12 eyes in eight out of the 100 patients had macular oedema clinica lly. Three scans in three patients could not be analysed because of poor sc an quality. In the additional group of scans 76 out of 88 eyes had macular oedema clinically. The scoring system had a specificity of 99% (95% CI 96-1 00) and sensitivity of 67% (95% CI 57-76). The predictive value of a negati ve test was 87% (95% CI 82-99), and that of a positive test was 95% (95% CI 86-99). The mean difference of the SCORE value between two observers was - 0.2 (95% CI -0.5 to +0.07). Conclusions-These data suggest that SCORE is potentially useful for detecti ng diabetic macular oedema in hospital diabetic patients.