Missed type 2 big bubble as an under-recognized cause of post-deep anterior lamellar keratoplasty double anterior chamber: A case report

Deep anterior lamellar keratoplasty (DALK) is commonly performed for stromal corneal pathology with healthy endothelium. Double anterior chamber is a recognized early postoperative complication, usually attributed to microperforation of Descemet membrane. We report an unusual case of early postoperative double anterior chamber following DALK in a 16-year-old girl with advanced keratoconus, caused by an unrecognized intraoperative type 2 big bubble. During pneumatic dissection, diffuse stromal whitening occurred after repeated air injection and no definite big bubble was appreciated intraoperatively. On the first postoperative day, a double anterior chamber was noted, and anterior segment optical coherence tomography confirmed Descemet membrane detachment. By day 3, partial resorption of the interface air revealed a central Descemet membrane tear. Retrospective review of the surgical video demonstrated a fleeting, thin, central bubble consistent with a missed type 2 big bubble. The patient was successfully managed with intracameral air descemetopexy combined with transcorneal suturing, resulting in complete reattachment of Descemet membrane and a favorable visual outcome. This case highlights missed type 2 big bubble as an under-recognized mechanism of postoperative double anterior chamber after DALK and emphasizes the importance of intraoperative recognition, preventive strategies, and timely intervention.