Fluid-Assisted Hydro-Bubble Technique With Newly Designed Cannula for Deep Anterior Lamellar Keratoplasty

Purpose This study was conducted to evaluate the efficacy and safety of the novel hydro-bubble technique (fluid-assisted Descemet's membrane (DM) exposure) with a newly designed cannula for inducing bare DM during deep anterior lamellar keratoplasty (DALK). Methods This retrospective study evaluated the results of DALK in which the hydro-bubble technique (fluid-assisted DM exposure) was performed with a newly designed cannula between April 2018 and March 2020. A femtosecond laser was used to create an initial incision with minimal remaining parenchyma. Balanced salt solution (BSS) was injected into the parenchyma using the newly designed cannula to induce bare DM. The success rate of hydro-bubble formation, visual outcomes, endothelial cell density, and complications were analyzed. Results The study included 39 patients with corneal opacity (n=19), corneal dystrophy (n=13), or keratoconus (n=6). Hydro-bubble formation was induced in 33 (84.6%) of these patients. At one year postoperatively, visual acuity was substantially better; the mean endothelial cell density at one month postoperatively was 1847 ± 622.1 cells/mm2. Intraoperative microperforation occurred in six cases (15.4%), but there were no instances of macroperforation or conversion to penetrating keratoplasty. Postoperative complications included a higher incidence of double anterior chamber, which was often associated with type 2 bubbles. Conclusion The hydro-bubble technique (fluid-assisted DM exposure) with a newly designed cannula is a promising alternative for inducing bare DM during DALK. It achieves a hydro-bubble formation success rate similar to the rate for the conventional big-bubble technique, while allowing greater control over hydro-bubble formation size and increasing visibility during surgery. Although further validation is needed, the enhanced safety and effectiveness of the hydro-bubble technique (fluid-assisted DM exposure) can facilitate better surgical management of corneal stromal pathologies.