Quantification of Diabetic Macular Edema with Heidelberg Retina Tomograph

Boo, Hee Don; Kim, Ha Kyoung; Kim, Hyung Chan

Abstract

Diabetic macular edema is a major cause of visual loss and it is difficult to be quantified.We investigated a method of assessment and volumetric quantification of diabetic macular edema with Heidelberg Retina Tomograph[HRT].Ten normal eyes of control group and 20 eyes with diabetic patients were studied.In 20 diabetic patients, 10 patients had macular edema and 10 patients had no macular edema. Macular edema was defined as any visible macular thickening within a circle centered at the fovea with 6mm in diameter. With HRT, the volumes above reference plane[VARP]bound by three consecutive circles centered at the fovea [diameter, 1, 2, and 3mm ]were measured. Measurements were repeated three times, and mean measurements were used for the analysis. Diabetic eyes with macular edema had statistically greater VARP than diabetic eyes without edema[p<0.01]and greater than normal eyes[p<0.01] for all three circles.There was no statistically significant difference between volumes measured in eyes without macular edema and normal control eyes[p>0.05]. The sensitivity of HRT was 90%, and the specificity was 100%. The VARP measured using HRT was found to be linearly correlated with visual acuity expressed on a logMAR scale[p<0.05]. From the above results, we concluded that HRT could identify diabetic macular edema by volumetric analysis and indicated a good relationship of volumetric changes with visual acuity.