Abstract
Purpose :
Intravitreal injections produce acute changes in intraocular pressure (IOP). We performed a prospective, observational clinical study to evaluate changes in blood flow that occur at the optic nerve after intravitreal bevacizumab injection using optical coherence tomography angiography (OCTA). We hypothesized that blood flow (perfusion density) to the optic nerve and peripapillary capillary network would acutely decrease secondary to the acute IOP elevation associated with intravitreal injection.
Methods :
Ten patients receiving intravitreal injections of bevacizumab for diabetic retinopathy, macular degeneration, and radiation retinopathy were included in this study. All patients were over the age of 18 with vision ≥20/80. Patients were excluded if they could not fixate for OCTA or if media opacity led to poor signal. Injection of 0.05 mL bevacizumab (1.25 mg) was given to 8 patients, 0.1mL bevacizumab (2.50 mg) was given to two patients with radiation retinopathy. All patients had peripapillary OCTA performed before and after injection. We reviewed perfusion density maps to measure blood flow changes that occur with the acute rise in IOP associated with intravitreal injections. Evaluation was performed on subdivisions of the optic nerve head vasculature and that of the radial peripapillary capillary (RPC) network. Paired t-tests were performed using SPSS software (v21) to analyze pre- and post-injection perfusion density within the areas of interest. A cut-off p<0.05 for significance was utilized.
Results :
The optic disc itself did not demonstrate a decrease in perfusion density after intravitreal injection. The superotemporal aspect of the disc showed a trend toward decreased perfusion. While the overall RPC network did not demonstrate a decrease in perfusion density after injection, the superotemporal subdivision of the RPC network was found to sustain a statistically significant decline in perfusion density. The superonasal RPC showed a trend toward decreased perfusion. See table 1 for details.
Conclusions :
Intravitreal injections produce an acute increase in IOP which may have an affect on the perfusion of the optic nerve and/or the peripapillary capillary network. Further studies are warranted to investigate longitudinal perfusion density changes of the optic nerve and peripapillary capillary network after intravitreal injections, including correlation with visual field analysis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.