Autofluorescence indexes as biomarkers for antiangiogenic loading dose outcome in diabetic macular edema

Abstract

Purpose: To evaluate the combination of fundus autofluorescence results with several clinical and structural variables into mathematical indexes to enhance their ability to predict visual and anatomical changes after the antivascular endothelial growth factor loading dose. Methods: Patients with diabetic macular edema were enrolled. Each patient had a comprehensive ophthalmological examination, contrast sensitivity, optical coherence tomography, and fundus autofluorescence assessment. All patients received three monthly doses of ziv-aflibercept and were followed each month for response assessment. Autofluorescence was classified according to its level into five grades. The grades were combined with other variables (best-corrected visual acuity, contrast sensitivity, central macular thickness, macular cube volume, and macular cube average thickness) into normalized indexes. Statistical assessment was done using a Spearman’s rank correlation coefficient, linear regression, and interobserver-agreement analysis. Results: There was a strong correlation between the fundus autofluorescence/baseline best-corrected visual acuity index and the fundus autofluorescence/contrast-sensitivity index at baseline with the best-corrected visual acuity after the third dose of ziv-aflibercept ( rs = −0.78, p = .000 and rs = −0.68, p = .0009 respectively). The fundus autofluorescence/baseline best-corrected visual acuity index and the fundus autofluorescence/contrast-sensitivity index, both at baseline had a mild correlation with the macular volume at 1 month of follow-up ( rs = 0.56, p = .008 and ( rs = 0.64, p = .002, respectively). Conclusion: This study suggests that it is possible to combine fundus autofluorescence results with functional and structural variables into normalized indexes that could potentially predict outcomes after antivascular endothelial growth factor loading dose in patients with diabetic macular edema.