A recent study evaluated how DME patients respond to intravitreal ranibizumab injections and found that certain OCT patterns may indicate when the therapeutic effects of anti-VEGF are limited.

The retrospective study included 216 eyes of 142 patients receiving intravitreal ranibizumab injections for DME. The researchers reviewed medical charts and spectral domain OCT images at baseline and at one, three, six, 12 and 24 months after the first injection. They categorized patients into four groups based on OCT findings: diffuse retinal thickening (n=36), cystoid macular edema (n=76), serous retinal detachment (n=42) and vitreomacular interface abnormalities (n=62).

The researchers observed significant central macula thickness improvements in all groups after the first month and at the second year of follow-up—except in the diffuse retinal thickening group, which did not achieve a significant reduction at two years. They suggested this may be due to a smaller central macular thickness at baseline in the group. OCT findings also revealed that patients with hyperreflective dots, metabolic parameters indicating hyperlipidemia and coronary artery disease had significantly less improvement in central macular thickness over the course of the study.

“More recent work has found that spectral domain OCT may be useful not only for observation of macular thickness and morphologic changes in DME, but also in the tracking of hyperreflective dots in the outer nuclear layer that may represent precursors of hard exudates, migrating retinal pigment epithelial cells or degenerated photoreceptor cells,” the researchers wrote in their paper.

They concluded that long-term intravitreal ranibizumab treatment may have decreased effectiveness in patients with diffuse retinal thickening, but in those with vitreomacular interface abnormalities, consistent treatment could result in improved central macular thickness.

Chen N, Chen W, Lai C, et al. Optical coherence tomography patterns as predictors of structural outcome after intravitreal ranibizumab in diabetic macular edema. Clin Ophthalmol. 2020;14:4023-30.