Multiplanar AS-OCT Detection of Clinically Occult Posterior Gas Bubble Dislocation After DSAEK

Descemet stripping automated endothelial keratoplasty (DSAEK) is a well-established surgical technique for the treatment of endothelial dysfunction, in which intracameral gas tamponade plays a critical role in graft adherence. We report the case of a 67-year-old pseudophakic woman with advanced Fuchs endothelial corneal dystrophy and symptomatic pseudophakic bullous keratopathy in the right eye, who presented with progressive visual deterioration and underwent DSAEK using an 8.25 mm donor graft inserted with a Busin glide and tamponaded with a 25% sulfur hexafluoride (SF6) gas–air mixture. On the first postoperative day, slit-lamp examination suggested an appropriate anterior chamber configuration and satisfactory graft attachment. However, detailed multiplanar anterior segment optical coherence tomography (AS-OCT), defined here as assessment using vertical, horizontal, and rotational scan orientations, revealed subtle posterior migration of the gas bubble beneath the iris plane. This clinically occult finding indicated altered anterior segment anatomy associated with a risk of secondary angle-closure mechanisms and raised concern for malignant glaucoma. Prompt surgical re-intervention was undertaken on postoperative day one, involving decompression of the misdirected gas bubble and reinjection of a centrally positioned tamponade. This resulted in restoration of normal anterior chamber configuration and stable graft adherence. Best-corrected visual acuity (BCVA) improved from 0.1 Snellen (1.0 logMAR) preoperatively to 0.7 Snellen (0.15 logMAR) at 2 weeks following surgery. This case highlights the added value of multiplanar AS-OCT in detecting clinically occult posterior gas migration after DSAEK, particularly when the abnormality is scan-orientation-dependent and not apparent on slit-lamp examination, thereby enabling timely intervention in the presence of a potentially sight-threatening postoperative configuration.