Abstract
Purpose: :
Blood flow into the eye is determined by the ocular perfusion pressure (OPP). OPP is the difference between the mean central retinal artery pressure (MCRAP) and the intraocular pressure (IOP) (OPP = MCRAP - IOP).1 Intravitreal anti-VEGF injections can increase intraocular pressure, thereby reducing retinal blood flow.2 The aim of this study was to investigate the effect of intravitreal injections on OPP.
Methods: :
The OPP, MCRAP, IOP and Ocular Pulse Amplitude (OPA) were measured using the Falck Medical Multifunction Applanation Tonometer (FAT1) in 20 eyes of 20 patients immediately before and after an intravitreal anti-VEGF injection. Twelve eyes received Avastin (0.5mg), and 8 eyes Lucentis (0.5mg). Mean upright ipsilateral brachial blood pressure (MBBP) was recorded.
Results: :
The mean age and MBBP was 79.7+/- 8 years and 93.4 +/-11 mmHg. MCRAP was 50% of MBBP. The mean post-injection increase in IOP was 11.4 mmHg, p = <0.0001 (29.9-18.5). The mean post-injection decrease in MCRAP was 10.8 mmHg, p = 0.006 (47.2-36.4). The mean post-injection decrease in OPP was 12.5 mmHg, p = 0.003 (28.6-16.1). Ocular perfusion pressure was reduced in 18 eyes following intravitreal injection. In 7 eyes, OPP declined to < 15 mmHg from increased IOP and decreased MCRAP. In 2 eyes the OPP decreased to zero from increased IOP and decreased MCRAP.
Conclusions: :
Based on the results of this study, intravitreal anti-VEGF injections can reduce MCRAP and OPP. This technology may help identify those patients at risk for having a decline in OPP, and therefore may enhance the safety of administration of anti-VEGF injections.1 Kaufman PL, Alm A. Adlers Physiology of the Eye. Tenth Edition 2003;764-67.2 Papadopoulou DN, Medrinos E, Mangioris G, et al. Intravitreal ranibizumab may induce retinal arteriolar vasoconstriction in patients with neovascular age-related macular degeneration. Ophthalmology.2009;116:1755-61.
Keywords: blood supply • drug toxicity/drug effects • intraocular pressure