Changes in the foveal microstructure after intravitreal bevacizumab application in patients with retinal vascular disease

Purpose: To investigate changes in the area of the foveal avascular zone (FAZ) in patients with retinal vascular disease. Patients and methods: This retrospective, consecutive study examined 53 eyes of 53 patients with macular edema due to branch retinal vein occlusion in 25 patients (47.2%) and nonproliferative diabetic retinopathy in 28 patients (52.8%). The macular edema was treated with an intravitreal injection of 0.05 mL equal to 1.25 mg bevacizumab. Before and 6-8 weeks after the injection, best corrected visual acuity, slit lamp biomicroscopy of the anterior segment and fundus, optical coherence tomography, and fluorescein angiography were conducted. The FAZ was manually circumscribed on early-phase angiography images and the area of the FAZ was measured. Results: The preoperative overall mean FAZ area was 0.327 ± 0.126 mm² (median 0.310 mm²). At the control consultation, the overall mean area was significantly larger (0.422 ± 0.259 mm²; median 0.380 mm²; P < 0.001). In the nonproliferative diabetic retinopathy subpopulation, the mean area was 0.361 ± 0.129 mm² (median 0.330 mm²) before bevacizumab application and 0.434 mm² at the follow-up visit (mean increase 0.071 mm²/19.7%). In the branch retinal vein occlusion group, the baseline FAZ area was 0.290 ± 0.115 mm² and 0.407 ± 0.350 mm² at follow-up (median 0.330 mm²; mean increase 0.117 mm²/40.3%). No cases of severe operation-associated complications were observed. Conclusion: The results confirm the safety of intravitreal bevacizumab injection in patients with macular edema due to nonproliferative diabetic retinopathy and branch retinal vein occlusion. The enlargement of the FAZ could be equivalent to an increase in retinal ischemia. These results may be transient; a potential vascular risk, however, when applying antivascular endothelial growth factor therapy in eyes with preexistent vascular disease must be considered.