Abstract
Purpose: :
Intravitreal injections of pharmacological agents have been the cornerstone of exudative age-related macular degeneration (AMD) treatment in the last several years. The role of the vitreo-retinal interface in the pathogenesis of AMD has recently been studied. The purpose of the present study is to evaluate the development and progression of epiretinal membranes (ERM) in patients being treated with anti-Vascular Endothelial Growth Factor (anti-VEGF) agents for AMD.
Methods: :
A retrospective study involving patients with a new diagnosis of exudative AMD was performed at the Cole Eye Institute between 2009 and 2011. All patients were naïve to treatment and did not have a clinically evident ERM at the time of diagnosis. Patients received intravitreal injections of bevacizumab or ranibizumab based on the discretion of the treating physician. Three observers (OSP, AY and RPS) analyzed the CirrusTM SDOCT high definition images at day 0 (date of initiation of therapy), at 6 months, and at 12 months. The observers were masked from the patient identifiers and dates of scans. ERMs were graded as being either grade zero (no ERM), grade 1 (extrafoveal ERM not separated from the internal limiting membrane- ILM), grade 2 (fovea-involving ERM not separate from the ILM), grade 3 (ERM with distinct separation from ILM) or grade 4 (distinct ERM with folds in the ILM). Secondary outcome measures included number of injections and presence of posterior vitreous detachment (PVD).
Results: :
22 eyes of 19 patients were included in the study. The weighted kappa value for agreement of ERM grading among all 3 observers was 0.79. For each pair of observers, substantial agreement was also found with kappa ranges from 0.70-0.88. The overall mean ERM grade increased significantly from baseline to the 6 month (p<0.001) and from the 6-month to the 12-month follow-up visit (p=0.005) for all 3 observers using the Wilcoxon-signed-rank test. Mixed effect regression analysis showed that the slope of ERM progression with time was independent of the presence or absence of PVD and to the number of injections.
Conclusions: :
In our study population, patients receiving intravitreal injections of anti-VEGF agents had a significant linear increasing trend in ERM progression over time, which was independent of the number of injections and to the presence of PVD. These results were valid for all three observers and the overall agreement between observers on the ERM grade was very good.
Keywords: age-related macular degeneration • vascular endothelial growth factor • imaging/image analysis: clinical