Aqueous Humor Levels of Vascular Endothelial Growth Factor Before and After Intravitreal Bevacizumab in Type 3 vs Type 1 and 2 Neovascularization. A Prospective, Case-Control Study

PURPOSE: To determine the aqueous levels of vascular endothelial growth factor (VEGF) in patients with type 3 neovascularization (NV) secondary to age-related macular degeneration (AMD) and to compare the levels of those with type 1 and 2 NV secondary to AMD before and after administration of intravitreal bevacizumab (IVB). DESIGN: Prospective, case-control study. METHODS: Aqueous samples were collected from 29 eyes of 29 patients with untreated wet AMD at baseline (day of the first IVB), month 1 (day of the second IVB), and month 2 (day of the third IVB). Among them, 10 eyes presented with type 1, 9 with type 2, and 10 with type 3 NV. A group of 14 aqueous samples from 14 patients who underwent cataract surgery without other ocular or systemic disease comprised the controls. Main outcome measures were concentration of VEGF at baseline and after IVB in the 3 NV groups; secondary outcome measures included best-corrected visual acuity (BCVA) and central macular thickness (CMT) changes after IVB. Levels of VEGF were determined by commercially available enzyme-linked immunosorbent assay kits. RESULTS: VEGF concentrations in aqueous humor at baseline were higher in patients with type 3 NV when compared to controls (P = .0001) and type 1 and 2 NV patients (P = .002 and P = .0001 respectively). At month 1, levels of VEGF were significantly reduced compared to baseline (P < .05) and significantly lower compared to the controls (P < .005) in each NV group. These low levels were maintained at the 2-month interval. BCVA significantly improved in type 1 and 2 NV groups (P < .05). CMT significantly reduced in each NV group compared to baseline (P < .05). CONCLUSION: In eyes with untreated wet AMD, aqueous levels of VEGF are significantly higher in type 3 NV than in type 1 or 2 NV. Regardless of the type of NV, aqueous VEGF levels significantly reduce 1 month after IVB as compared to both the baseline measurements and the values recorded in age-matched controls. These decreases are maintained at 2 months after administering a second IVB 30 days after the initial injection.