Distribution of intraretinal exudates in diabetic macular edema during anti-vascular endothelial growth factor therapy observed by spectral domain optical coherence tomography and fundus photography.

Purpose: To evaluate changes in the distribution and morphology of intraretinal microexudates and hard exudates (HEs) during intravitreal anti-vascular endothelial growth factor therapy in patients with persistent diabetic macular edema.
Methods: Twenty-four patients with persistent diabetic macular edema after photocoagulation were investigated in this prospective cohort study. Each eye was assigned to a loading dose of three anti-vascular endothelial growth factor treatments at monthly intervals. Additional single treatments were performed if diabetic macular edema persisted or recurred. Intraretinal exudates were analyzed over 6 months using spectral domain optical coherence tomography (SD-OCT) and fundus photography.
Results: Before treatment, microexudates were detected by SD-OCT as hyperreflective foci in 24 eyes, whereas HEs were seen in 22 eyes. During therapy, HE increased significantly in number and size. This was accompanied by accumulation of microexudates in the outer retina. Enlargement of hyperreflective structures in SD-OCT was accompanied by enlargement of HE at corresponding fundus locations. A rapid reduction in diabetic macular edema was seen in all patients, but to varying degrees. Patients with hemoglobin A1c levels <7% and serum cholesterol <200 mg/dL formed fewer HEs and featured more edema reduction and visual acuity gain.
Conclusion: Diabetic macular edema reduction during intravitreal anti-vascular endothelial growth factor therapy was accompanied by dynamic rearrangement of intraretinal exudates at corresponding locations in fundus photography and SD-OCT. Intraretinal aggregates of microexudates detectable as hyperreflective foci by SD-OCT may compose and precede HE before they become clinically visible.