Design of a Precision Needle for Injection of Fluid into the Suprachoroidal Space of the Eye for the Treatment of Retinal Detachment

Abstract

Rhegmatogenous retinal detachment (RRD) is a vision-threatening condition that affects 10 to 18 per 100,000 people in the United States annually [1]. The current standard for treatment is pars plana vitrectomy (PPV), which is an invasive and expensive surgical procedure that leaves patients unable to perform usual activities for four to six weeks. In addition, current methods tend to produce distorted vision upon recovery. In-office Suprachoroidal Viscopexy™ (SCVEXY™) is a minimally invasive technique recently developed by Dr. Rajeev Muni for treating rhegmatogenous retinal detachment (RRD) which has been performed on a handful of people [2]. This procedure has the potential to greatly reduce the cost and recovery time of RRD while also improving the quality of the repair. It can be performed with no incision, no tamponade agent, and no patient post-op positioning requirements [2]. SCVEXY works by injecting viscous fluid into the suprachoroidal space, a “potential space” between the sclera and choroid, creating a “bleb” of fluid underneath the tear that pushes the choroid towards the retina and allows it to reattach. However, difficulty in safely injecting into this space at the location of the retinal tear currently limits the widespread utilization of the technique. If this procedure was made reliably safe, it could greatly change how retinal detachments are treated and improve patient outcomes. The primary difficulty arises in precisely locating the suprachoroidal space in order to inject the viscous fluid. The thickness of the sclera varies from patient to patient and between locations on the eye. Additionally, the scleral and choroidal tissues are very thin, leaving little room for positional error. Hemorrhage may occur if the needle punctures through the choroid and into the subretinal space, which could lead to bad outcomes. This work presents a device developed to minimally invasively reach posterior segments of the eye, deploy an injection needle in-situ with high resolution, sense when the needle tip has passed into the suprachoroidal space (SCS), and inject a viscous fluid. Not only will this device be used to treat retinal detachment in a minimally invasive manner, but it could also be used for drug injection or fluid aspiration via the suprachoroidal and subretinal spaces for treatment of a variety of posterior ocular diseases.