Partial Fluid-Air Exchange Enhances Submacular Injection of Retinal Sheets

Background and Objective: Subretinal therapeutics represent a growing area of research with diverse clinical applications. Inadvertent reflux of therapeutic into the vitreous after delivery represents a surgical challenge that leads to therapeutic loss. This study sought to evaluate a modified technique utilizing partial fluid-air exchange (pFAX) to reduce reflux. Materials and Methods: This single-center study included 18 eyes of nine live pigs. Human iPSC-derived retinal sheets (Sumitomo Pharma) were injected into the subretinal space utilizing pFAX. Results: Retinal sheets were successfully delivered in all eyes. Incorporating pFAX reduced intraocular turbulence and reflux by maintaining (1) stable intraocular pressure, (2) self-sealing wound closure, and (3) subretinal bleb stability. When improper delivery or reflux of sheets did occur, reaspiration and reinjection was much easier with pFAX than with a fluid-filled eye. Conclusion: Incorporating pFAX reduced reflux during subretinal injection of retinal sheets. This technique may enhance current and future applications of subretinal surgery.