Purpose: To investigate the association between the characteristics of foveal cystoid spaces and short-term responsiveness to ranibizumab treatment for diabetic macular edema (DME) at 3 months from the initial injection.
Methods: We retrospectively reviewed 66 eyes of 61 patients with center-involved DME who received three consecutive ranibizumab injections and following as-needed administrations. We evaluated the relationship between visual improvement at 3 months and the preoperative optical coherence tomography (OCT) parameters including hyperreflective foci, heterogeneous OCT reflectivity, mean levels of OCT reflectivity and height of foveal cystoid spaces.
Results: Twenty-three eyes without preoperative hyperreflective foci in the foveal cystoid spaces had significantly greater improvement in the logarithm of the minimum angle of resolution visual acuity (logMAR VA) at 3 months than 43 eyes with foci (P = 0.006). That was similar to the greater reduction in CSF thickness in eyes without lesions after treatment at the same time point (P < 0.001). VA improvement at 3 months was not associated with the height (R = 0.215, P = 0.083) or the reflectivity levels (R = -0.079, P = 0.538) of foveal cystoid spaces. There were no differences in VA changes between eyes with and without heterogeneous reflectivity in foveal cystoid spaces (P = 0.297). Multivariate analyses showed that logMAR VA and the absence of hyperreflective foci in foveal cystoid spaces were associated with VA improvement at 3 months.
Conclusion: Hyperreflective foci in foveal cystoid spaces at baseline predict poorer short-term responsiveness to ranibizumab injections for DME.
Keywords: Cystoid spaces; Diabetic macular edema; Hyperreflective foci; Ranibizumab; Spectral-domain optical coherence tomography.