To assess the correlation between the features of optical coherence tomography (OCT) and fluorescein angiography in clinically significant diabetic macular edema.

Retrospective observational case series.

This study involved 145 eyes (91 patients) with clinically significant diabetic macular edema. The fluorescein angiography features were categorized into focal leakage type, diffuse leakage type, and diffuse cystoid leakage type. The OCT features were categorized into four types: type 1, thickening with homogenous optical reflectivity; type 2, thickening with markedly decreased optical reflectivity in the outer retinal layer; type 3A, foveolar detachment without traction; and type 3B, foveolar detachment with apparent vitreofoveal traction. The correlation between fluorescein angiography types and OCT types were analyzed, and their associations with visual acuity, central foveal thickness. and stages of diabetic retinopathy were evaluated.

The prevalence of OCT type 1 was higher in the focal leakage type (73.0%) and in the diffuse leakage type (58.9%) than in the diffuse cystoid leakage type (3.8%) of fluorescein angiography (P < .0001). The prevalence of OCT type 2 and 3A was higher in the diffuse cystoid leakage type (57.7% and 34.6%, respectively) than in the focal leakage type (20.6% and 3.2%) or diffuse leakage type(28.6% and 10.7%; P < .0001). The stages of retinopathy correlated with fluorescein angiography types (P = .016). Optical coherence tomography type 1 and the focal leakage type of fluorescein angiography showed the least foveal thickness and the best visual acuity (P < .05).

There was a significant correlation between the features of OCT and fluorescein angiography in clinically significant diabetic macular edema. The combined data from both OCT and fluorescein angiography may provide a clearer understanding of the anatomic and physiologic characteristics of clinically significant diabetic macular edema.