Purpose: The purpose of this study was to investigate the effect of intravitreal bevacizumab on an experimental rabbit model of penetrating posterior ocular injury.
Methods: The right eyes of 40 white New Zealand rabbits were included in a penetrating posterior ocular injury model that was consisted of a 5-mm circumferential incision placed 8 mm behind the limbus at the supratemporal quadrant. They were randomly divided into two groups. The rabbits in Group 1 (n = 20) received 1.25 mg (0.05 mL) of intravitreal bevacizumab via pars plana injection and those in Group 2 (control group, n = 20) received 0.05 mL of intravitreal balanced salt solution. On Day 28, the eyes were enucleated and evaluated by gross inspection and light microscopy. Clearance time of vitreous hemorrhage, presence of fibrous proliferation or retinal detachment, greatest linear dimension of fibrosis, and grade of fibrous extension were regarded as outcome measures. Nominal variables were evaluated by the chi-square or the Fisher's exact test; continuous variables were evaluated using the Mann-Whitney U test.
Results: At the end of the surgery, all the eyes had moderate (n = 9 and 7 in the case and control groups, respectively) or severe vitreous hemorrhage (n = 11 and 13 in the case and control groups, respectively) (P = 0.52). Average clearance time of vitreous hemorrhage was 3.42 ± 2.71 and 6.47 ± 3.58 days in bevacizumab and control groups, respectively (P = 0.01). The incidence of ophthalmoscopically visible fibrous proliferation was 31.6% in the bevacizumab group and 63.2% in the control group (P = 0.05). The greatest linear dimension of fibrosis was 0.91 ± 1.14 mm in the bevacizumab group and 2.00 ± 1.58 mm in the control group (P = 0.02). Retinal detachment rate was 11% (n = 2, all rhegmatogenous) and 21% (n = 4, 2 rhegmatogenous and 2 tractional) in the bevacizumab and control groups, respectively (P = 0.66). Choroidal congestion, optic disk edema, and macular edema were seen in 1 eye (5.5%) of the bevacizumab group, whereas they were found in 4 (22%), 4 (22%) and 3 (16.5%) eyes of the control group, respectively. These differences, however, did not reach statistical significance.
Conclusion: This study showed that intravitreal injection of bevacizumab may reduce the extent of fibrovascular and/or fibrocellular proliferation and may accentuate the clearance of vitreous hemorrhage after an experimental model of posterior penetrating ocular injury in rabbits. These alterations may affect the long-term anatomical and/or functional success rate of posterior segment surgeries in these eyes.