Authors (including presenting author) :
Dr. Jolly Lok-yee TSUI, MRCSEd(Ophth)
Dr. Ivan Hong-wan LAU, MBBS
Dr. Sophia Ling LI, MBBS, PhD
Dr. Noel Ching-yan CHAN, FRCSEd(Ophth), FCOphthHK
Professor Alvin L YOUNG, FRCOphth, FCOphthHK
Affiliation :
Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.
Introduction :
Intravitreal anti-vascular endothelial growth factors (anti-VEGF) have been widely used in the treatment of various retinal pathologies such as neovascular age-related macular degeneration (ARMD)1, 2 and macular oedema associated with diabetic retinopathy (DME)3 or retinal venous occlusion (RVO).4 Although it is generally recognized as a safe procedure, from time to time there are case reports of complications like acute angle closure5 and significant short-term intraocular pressure (IOP) rises leading to retinal arterial occlusion.6 Sudden expansion in the vitreous volume is proposed to be responsible for the short-term IOP increase immediately after intravitreal anti-VEGF injections, and the practice of IOP monitoring post-injection varies among institutions. Even though the effect might be transient, visual damage can be incurred especially in patients with preexisting glaucoma. Animal models have shown that acute rise in IOP can lead to axonal transport blockade to the optic nerve head,7 and more severe damage was noted in higher IOP rise. Acute rise in IOP can also lead to decreased juxtapapillary retinal and optic nerve head blood flow that is proportional to the severity of IOP rise, resulting in ocular ischaemia and functional damage if remained uncontrolled.8 As the central vision of patients with retinal disorders requiring anti-VEGF is usually already impaired, it is all the more important that every effort is made to preserve the peripheral vision and optic nerve function, which is important for night vision and navigation for activities of daily living. Any significant IOP elevation should be avoided and timely treatment should be offered to those with sustained IOP rise. So far there is no guideline regarding the monitoring of short-term IOP changes after intravitreal anti-VEGF injections and there are limited studies evaluating predictors for severe IOP spikes. In order to stratify patients at risk of more significant and prolonged IOP spikes, this study examined the frequency and severity of IOP rise 5, 15 and 30 minutes after intravitreal anti-VEGF injections and explored potential predictive factors for these IOP elevations.
Objectives :
To explore the pattern of intraocular pressure (IOP) changes after intravitreal anti-vascular endothelial growth factors (anti-VEGF) injections and associated predictive factors.
Methodology :
48 patients were recruited into this prospective case-series and IOP of injected eyes were measured using Goldmann Applanation Tonometry at baseline, 5, 15 and 30 minutes after intravitreal anti-VEGF injections. Potential predictive factors including age, gender, lens status, axial length, history of glaucoma, number of previous intravitreal anti-VEGF injections, diagnosis requiring anti-VEGF injections and post-injection vitreous reflux were analysed.
Result & Outcome :
The mean IOP at baseline and 5, 15 and 30 minutes after intravitreal anti-VEGF injection were 16.2 ± 3.2 mmHg, 32.7 ± 10.5 mmHg, 21.7 ± 5.3 mmHg and 18.3 ± 3.8 mmHg respectively; and the mean difference in IOP compared to baseline at 5, 15 and 30 minutes were 16.4 ± 10.0 mmHg, 5.5 ± 4.7 mmHg and 2.1 ± 3.3 mmHg respectively. Up to 48% of the enrolled eyes demonstrated ≥15 mmHg increase in IOP from baseline at 5 minutes after the intravitreal injection. All IOP spikes normalized within 60 minutes. Multivariate linear regression showed statistically significant correlation between the number of previous intravitreal anti-VEGF injection and IOP at 5 minutes post-injection (b = 0.55, SE = 0.26, p-value = 0.04). Other predictive factors were not statistically significant.
