Treatment of neovascularization in the eye by photo-mediated ultrasound therapy

Abstract

Neovascularization in the eye is a common disorder. Abnormal microvessels can develop in the cornea, retina, or choroid of the eye, leading to severe vision loss if left untreated. Current treatment methods carry disadvantages or side effects, such as drug-resistance or damage to the surrounding healthy tissues. By applying synchronized laser pulses and ultrasound bursts, we developed a technique, termed photo-mediated ultrasound therapy (PUT), as a localized antivascular method based on the enhanced cavitation mechanism. PUT takes advantage of the high native optical contrast between blood and surrounding tissues, and has the unique capability to self-target microvessels without damaging surrounding tissues. The technique utilizes nanosecond laser pulses, which is spatially and temporally synchronized with low duty-cycle ultrasound bursts of sub-MHz frequencies at the targeted microvessels. We have tested the feasibility of PUT on the removal of neovascularization in the cornea, retina and choroid in a rabbit eye model. We found that neovascularization in the eye could be greatly reduced after PUT, and the occlusion of microvessels could last up to 4 weeks. In conclusion, PUT holds significant promises as a non-invasive method to precisely remove microvessels in neurovascular eye diseases by more selectively treating vasculature with minimized side-effects.