En Face Spectral-Domain Optical Coherence Tomography Imaging of Outer Retinal Hard Exudates in Diabetic Macular Edema Based on Optical Coherence Tomography Patterns

Background and Objective: To evaluate en face spectral-domain optical coherence tomography (SD-OCT) findings of the outer retinal hard exudates in diabetic macular edema (DME). Patients and Methods: Exploratory analyses of prospective and consecutive case series. Fifty-five eyes treated with intravitreal ranibizumab (IVR) (Lucentis; Genentech, South San Francisco, CA) for 12 months were classified according to OCT features of DME: diffuse retinal thickening (DRT), cystoid macular edema (CME), and serous retinal detachment (SRD). Area fraction of outer nuclear layer (ONL) hard exudates (HEs) was assessed from en face OCT images. Results: Area fraction of ONL HEs increased from 1.45% +/- 1.22% to 2.24% +/- 1.31% in DRT and from 2.24% +/- 1.85% to 3.25% +/- 1.52% in CME. HE gain was greatest during first 3 months (DRT = 0.83%; CME = 1.25%). SRD showed no difference in HEs (P = .462). Conclusions: ONL HEs increased in DRT and CME at month 12 following IVR. Rapid gain of HEs was found during the initial loading phase of IVR.