Purpose: Evaluation of the influence of long-term intravitreal anti-vascular endothelial growth factor treatment on preexisting retinal microstructural alterations in patients with diabetic macular edema.
Methods: Eyes with diabetic macular edema and a history of ≥ 20 intravitreal anti-vascular endothelial growth factor (aflibercept and/or ranibizumab) injections were included in this retrospective study. Primary outcome was the extent of disorganization of retinal inner layers, alterations at the outer plexiform layer/Henle fiber layer junction, disruption of external limiting membrane/ellipsoid zone, disruption of retinal pigment epithelium/Bruch complex, and retinal atrophy at baseline versus after ≥ 20 intravitreal injections as visualized by spectral-domain optical coherence tomography images.
Results: Of 383 eyes screened, 37 eyes were included in the current study. With the exception of outer plexiform layer/Henle fiber layer junction restoration, no significant changes regarding microstructural alterations between baseline and end of study were encountered after long-term anti-vascular endothelial growth factor (disorganization of retinal inner layers P = 0.381, outer plexiform layer/Henle fiber layer junction P = 0.001, external limiting membrane/ellipsoid zone P = 0.524, retinal pigment epithelium/Bruch complex P = 0.122, retinal atrophy P = 0.317). Best-corrected visual acuity significantly increased over the course of the study, corresponding to central retinal thickness and intraretinal fluid reduction (all P < 0.0001). The extent of microstructural alterations was negatively correlated with best-corrected visual acuity (P < 0.05).
Conclusion: Apart from outer plexiform layer/Henle fiber layer junction layer restoration, no effect on preexisting retinal alterations was encountered after long-term intravitreal injections. Thus, intravitreal ranibizumab or aflibercept did not have a major effect (neither positive nor negative) on microstructural alterations.