We thank Drs Takkar and Azad for their interest and comments regarding our recent publication titled “Effect of Serial Intrasilicone Oil Bevacizumab Injections in Eyes With Recurrent Proliferative Vitreoretinopathy Retinal Detachment.”
As a point of clarification to the authors’ correspondence, all 20 eyes in the intervention group that received intrasilicone oil injections of bevacizumab had previously undergone pars plana vitrectomy (PPV) surgery for retinal detachment (RD). While 10 eyes had also previously undergone a scleral buckling procedure, all eyes were previously vitrectomized at the time of enrollment in the study. As the authors suggest, while a comparative analysis of eyes with recurrent proliferative vitreoretinopathy (PVR) detachment following scleral buckling procedure alone vs PPV alone would be of interest in regard to bevacizumab treatment effect, this cannot be completed with our study cohort.
Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) remain molecular targets of interest for the prevention of PVR. We noted several potential reasons for the lack of observed effect of intrasilicone oil bevacizumab injections in our study, including altered half-life of bevacizumab in silicone oil and inclusion of only patients with advanced stages of PVR (grade C). To the point of Drs Takkar and Azad, we agree that anti-VEGF agents may result in different outcomes in eyes without prior vitrectomy or without silicone oil, or if utilized in eyes with milder forms of PVR or with a different treatment schedule. As we stated in the manuscript, perhaps evaluating anti-VEGF agents in “high-risk primary RD patients who have earlier stages of PVR (grades A or B) or other risk factors for PVR development (eg, associated vitreous hemorrhage or uveitis, extensive retinal detachments, large retinal breaks, etc) may be a better strategy.” Such a study would be of considerable interest yet would require a considerably larger enrollment, given the low rate of PVR development following primary RD repair surgery. We also agree that epiretinal membrane (ERM) formation may be influenced by many factors following RD repair surgery, including the anatomy of the posterior hyaloid, and is an imperfect measure of PVR activity; as such, ERM formation was included only as a secondary outcome.
Crosstalk between VEGF and PDGF remains a topic of great interest in regard to the treatment and prevention of PVR. Efforts to evaluate anti-VEGF and anti-PDGF agents as well as to identify novel molecular targets in patients with or at risk for PVR are certainly deserving and worthy of future study.