Abstract
Purpose :
Treatment of concurrent geographic atrophy and neovascular age-related macular degeneration currently requires ocular injection of a large volume of therapeutic agents and careful management of intraocular pressure (IOP). Potential solutions, including paracentesis and delay between injections present hurdles to clinical implementation. We aimed to understand how a device designed to acquire vitreous liquid biopsy incidental to intravitreal injection could mitigate post-injection IOP spike in this workflow.
Methods :
Porcine eyes chilled on water ice were used <36 hours after collection. IOP was raised to a target pressure of 16mmHg (14.1 - 25.4mmHg) by intravitreal injection with BSS. The eye was closed to fluid transfer and IOP was monitored in several scenarios using Tono-VeraVet with “Dog” calibration.
Anterior segment injections were performed to simulate the highly liquefied vitreous environment of an aged human eye. Needles were left in place after injections to limit refluxed outflow through wound sites. Control Scenario (7 eyes): Injection of 100µL BSS followed immediately by a separate injection of 50µL BSS using traditional 0.5mL staked needle insulin syringes from BD. Test Scenario (7 eyes): Liquid biopsy coupled with co-injection of 100µL BSS using the VitreoDx experimental injection device, followed immediately by separate injection of 50µL BSS using an insulin syringe.
The rate of passive pressure decline was observed in three eyes by first increasing the pressure to a high level by intravitreal injection and monitoring the pressure as it returned toward normal.
Results :
For the control scenario, baseline pressure was 16.6 ± 2.3mmHg (mean ± SD), reached 68.3 ± 17.5mmHg after the first injection of 100µL and exceeded the measurement range of the device (>99mmHg) after the second 50µL injection. For the test scenario, baseline pressure was 17.1 ± 3.7mmHg, dipped to 11.2 ± 1.3mmHg immediately after the aspiration portion of the procedure, before recovering to 19.9 ±10.5mmHg after the first injection, and reached 32.2 ± 20.6mmHg after the second injection.
The time required for eyes to fall passively from 70mmHg to a pressure of 30mmHg was 11min.
Conclusions :
Liquid biopsy incidental to injection, when applied to a first 100µL dose significantly mitigates the IOP spike associated with a combination 100µL + 50µL dose delivered in rapid succession.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.