Posterior Segment Pressurization With Intravitreal Balanced Salt Solution to Stabilize Anterior Chamber Gas During Endothelial Keratoplasty

PURPOSE: To describe a novel technique for managing anterior chamber (AC) instability during endothelial keratoplasty in eyes with compromised anterior segment architecture through posterior segment pressurization via intravitreal balanced salt solution (BSS) injection. METHODS: In eyes with distorted iris anatomy, large peripheral iridectomies, prior vitrectomy, or iris-lens diaphragm instability undergoing Descemet stripping automated endothelial keratoplasty (DSAEK) or Descemet membrane endothelial keratoplasty, intraocular air or gas may migrate posteriorly, destabilizing the AC and compromising graft apposition. We describe a technique in which approximately 0.2 mL of BSS is injected through the pars plana into the vitreous cavity using a 30-gauge needle, providing transient posterior segment pressurization to stabilize the globe. After injection, the needle is maintained in position with gentle plunger control for approximately 2 minutes to allow stabilization of posterior segment pressure and sustained globe firmness. RESULTS: The technique was successfully applied in 3 complex cases: 1) an 81-year-old man with atonic pupil, postvitrectomy, and glaucoma tube shunt undergoing DSAEK; 2) an 82-year-old female postvitrectomy patient undergoing DSAEK; and 3) 77-year-old man with large peripheral iridectomy undergoing Descemet membrane endothelial keratoplasty. All cases achieved stable AC configuration and secure graft attachment without excessive air/gas fill or posterior gas migration. CONCLUSIONS: Posterior intravitreal BSS injection provides an effective method to stabilize the iris-lens diaphragm and maintain AC architecture during endothelial keratoplasty when conventional air/gas injection alone is insufficient.