Abstract
Purpose :
Glaucoma studies have shown that patients with elevated intraocular pressure (IOP) have poor optic nerve perfusion. Furthermore, an increase in IOP immediately after intravitreal anti-VEGF injection can result in a transient decrease of mean ocular perfusion pressure [Lee BMC 2016]. The purpose of this study is to quantify the perfusion of the optic nerve and macula in response to Anti-VEGF injection in diabetics using OCT angiography.
Methods :
Optic Nerve (ONH) 4.5x4.5 mm and macula 3x3 mm angiography scans were obtained using CIRRUS™ HD-OCT 5000 with AngioPlex® OCT Angiography (ZEISS, Dublin, CA) on a diabetics receiving anti-VEGF as part of clinical care. Prior to injection, Tono-Pen AVIA®( Reichert Technologies, Depew, NY) was used to measure baseline IOP. Post injection, IOP, ONH scan and macula scan were performed at 1, 10, and 20 minutes. Angiography metrics were calculated at each time point with CIRRUS 11.0 software. ONH perfusion was calculated based on the vasculature network between internal limiting membrane (ILM) and retinal nerve fiber layer. Macular perfusion was calculated based on the vasculature network between ILM and outer boundary of inner plexiform layer. For each diabetic, scans from a normal subject with age within 5 years were retrospectively identified and evaluated for comparison.
Results :
Figure 1 shows macular and optic nerve perfusion of normal and diseased patients. At baseline, the macular perfusion of 8 diabetics (Age: 57 +/- 11) was significantly less perfused (p=0.01) than 8 normals (Age: 53 +/- 10) while the perfusion at the optic nerve was similar (p=0.16) to 8 normals (Age: 55 +/- 10). Post injection, IOP increased (p=0.002) and optic nerve head perfusion decreased (p=0.045). Macular perfusion post-injection decreased insignificantly (p=0.10). Figure 2 shows IOP and ONH perfusion changes.
Conclusions :
Diabetics have a less perfused macula, but a normally perfused optic nerve compared to normals at baseline. IOP increased in all patients post-injection while optic nerve perfusion decreased in 6 out of 8 patients. Macular perfusion did not show a specific trend. However, after 20 minutes, measured parameters tended to return to baseline. AngioPlex OCTA demonstrates the transient effect on optic nerve perfusion expected in response to IOP increase due to intravitreal injection.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.