Abstract
Purpose :
Intravitreal injections produce acute intraocular pressure (IOP) changes. We performed a prospective, observational clinical study to analyze changes in macular blood flow and macular thickness that occur post-injection using optical coherence tomography (OCT) angiography. We hypothesized that blood flow would acutely decrease with IOP elevations associated with intravitreal injections.
Methods :
All patients over age 18 that received intravitreal injections with at least 20/80 vision were included. Patients were excluded only if they couldn't fixate or media opacities led to poor signal. Ten patients receiving injections for diabetic retinopathy, macular degeneration, and radiation retinopathy were included. Injections of 0.05mL Avastin (1.25mg) were given to 8 patients, and 0.1mL Avastin (2.50mg) given to two radiation retinopathy patients. All patients had macular OCT angiography performed before and immediately after injections. IOP was checked immediately post-injection. Angiographic density maps were reviewed to measure blood flow changes related to intravitreal injections and associated acute IOP changes. The macula was subdivided into deep and superficial layers, with further subdivisions into macula, fovea, parafovea, superior hemifield, inferior hemifield, temporal, superior, nasal, and inferior. Changes in macular thickness were also measured. Paired t-testing in SPSS (v21) was used to analyze each patient’s pre—and post-injection angiographic density.
Results :
Statistically significant changes in angiographic density (p<0.05) were observed only with superficial areas of the macula, and not in any deep macular measurements. Specifically, angiographic density in the overall macula, superior, superior hemifield, temporal, inferior, inferior hemifield, and nasal areas of the superficial macula were significantly decreased post-injection (Table 1). Deep layers were not significantly different pre- and post-injection. Overall macular thickness on OCT was not statistically different pre- and post-injection except in the nasal aspect, where it was increased.
Conclusions :
Intravitreal injections produce acute changes in intraocular pressure (IOP) and changes in retinal blood flow. This preliminary study of 10 patients shows that superficial and not deep layers of the macula are affected by these changes, and that nasal OCT thickness increases while other areas are not significantly affected acutely after injections.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.