Abstract
Purpose :
Angiogenesis is a leading cause of vision loss in numerous diseases including macular degeneration. Treatment of choroidal neovascularization (CNV) currently relies primarily on intravitreal injection of anti-vascular endothelial growth factor therapy due to side effects from conventional laser therapy. This study evaluates the efficacy and safety of a novel treatment combining synchronized, concurrent nanosecond laser pulses and ultrasound, termed photo-mediated ultrasound therapy (PUT), in a clinically-relevant rabbit CNV model.
Methods :
CNV was created by subretinal injection of Matrigel and vascular endothelial growth factor in 10 New Zealand white rabbits. PUT treatment was performed in 6 rabbits and control laser-only and ultrasound-only were performed in 2 rabbits each. Treatment efficacy was evaluated through fundus photography and fluorescein angiography (FA) leakage area quantification at 3 days and 1,2, and 4 weeks. Rabbits were sacrificed for histopathology at 3 months to evaluate the safety.
Results :
FA demonstrated regions of hypofluorescence after PUT treatment. The relative FA intensity was statistically significantly reduced (p < 0.001) at all times after PUT treatment: 26.6% ± 8.7% at 3 days, 27.2% ± 6.2% at 1 week, 27.8% ± 2.6% at 2 weeks, and 32.1% ± 3.2% at 4 weeks (Fig 1). The 2 control groups (laser-only and ultrasound-only treatment) showed no statistically significant difference at any time point. Safety evaluation with histopathology demonstrated that PUT did not result in morphologic changes to the neurosensory retina at 3 months.
Conclusions :
This study demonstrates for the first time the safety and efficacy of synchronized, concurrent nanosecond laser and ultrasound for the treatment of CNV in a clinically-relevant rabbit model. PUT can safely reduce CNV leakage for at least 1 month after treatment.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.