Clinical Translation of Retinal Thermofusion for Rapid Retinal Detachment Repair Without Tamponade
Abstract
Background and Rationale: The retina is the film-like, light-sensitive nerve tissue lining the inside of the eye. If a retinal tear develops as a result of trauma or degenerative vitreous changes, the retina separates from its underlying retinal pigmented epithelium (RPE) -- like an inner tube collapsing in a tire. Repair requires surgery to deliberately injure the tear margin. This initiates a slow healing response, like a scar, supported by a bubble of dissolving gas or viscous liquid inside the eye to hold both tissues together -- just like stitches in a wound. During the 100-year evolution of the surgical technique, heated wires and freezing probes have been used to create the required wound; nowadays photocoagulating lasers are used. When a gas bubble is used for support during scar formation, it badly blurs vision, prohibits normal activities and, critically, prevents aeromedical evacuation from the combat zone for two or more weeks postoperatively because increasing gas pressure during ascent would result in total blindness. When a liquid vitreous substitute is required, repeat surgery is needed to remove the liquid before secondary damage occurs. An intraoperative seal of tears independent of any support offers simplified surgery, faster recovery, less repeat surgery, and lower cost to the health system. With our previous award, we explored how to optimize retinal seal formation and showed that if all the fluid remaining under the retinal tear edge is first thoroughly dried before photocoagulation applied, the torn retina can be strongly fused back onto its underlying RPE in a single operation. It is as if the tissues are instantaneously fused together, or how two eggs become unified if touching when cooked. With a total seal preventing further leakage, no tamponade is necessary. This understanding underlies the development of a novel approach for retinal detachment repair that requires neither gas nor liquid support. We use low-power infrared laser energy delivered via a novel intraocular fiberoptic probe to heat water molecules selectively and locally so that they leave the liquid phase as a vapor that is blown away by a gentle air stream coaxially delivered via the same probe. Our method provides targeted and focal elimination of subretinal fluid with minimal damage to surrounding tissue. Immediately after drying, we switch the laser to a higher power for photocoagulation, which fuses the dried retinal edge back onto its original position on the RPE. By producing an instantaneous seal, we eliminate multiple steps from the current surgical method, and, critically, there is no need for post-operative gas or liquid support. Objectives and Aims: In this project our objective is to translate this improved detachment repair method into routine clinical care. Specifically, our aims are to (a) develop a training module for retinal surgeons to master the critical components of the modified surgical technique prior to performing it on patients, (b) evaluate the surgeon experience, and performance of a pre-production novel laser console and intraocular laser handpiece probe to inform the final design specifications prior to commercial production, and (c) evaluate, in a pilot clinical human trial, the effectiveness of the technique to achieve retinal reattachment without gas or liquid support. Approach: We will first use our ex vivo model of retinal detachment to ensure that surgeons are accurate with judging the endpoint of adequate dehydration prior to commencing photocoagulation. This judgement will be taught in the wet lab on both abattoir-sourced porcine eyes and human eye bank donor eyes so that there should be no significant learning curve when surgeons transition this method to patient surgery. This training will involve a preproduction prototype device, with surgeons providing feedback to identify any possible ergonomic refinements prior to commercial production. Milestones: The short-t
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 05, 2021
- Source ID
- W81XWH2110730
Entities
People
- Wilson Heriot
Organizations
- Centre for Eye Research Australia
- United States Army