Study finds, Microscope-Integrated Intraoperative OCT–Guided
The purpose of this study was to evaluate the feasibility of microscope-integrated intraoperative optical coherence tomography (OCT) for real-time quantitative analysis of surgical planes in big-bubble deep anterior lamellar keratoplasty (DALK).

In this interventional case series, intraoperative OCT-guided big-bubble DALK was performed in 16 consecutive eyes of 16 patients with keratoconus. Trephination depth was measured using the intraoperative OCT caliper tool. Aiming for a depth within 150 microm from the endothelial surface, the trephination groove was extended to a deeper plane using a 15-degree blade. Repeat OCT scans were taken to measure residual stromal thickness before insertion of the DALK probe from the bottom of the extended trephination.

--After trephination, residual stromal thickness exceeded 150 microm in all eyes and averaged 257.1 ± 42.5 microm.

--In each case, the initial trephination groove was extended to a depth within 150 microm from the endothelial surface. Big-bubble formation was achieved in 12 eyes.

--Type 1 bubble was obtained in 11 eyes. Perforation requiring conversion to penetrating keratoplasty occurred in 4 eyes during insertion of the cannula into a residual stromal bed of less than 100 microm (n = 2; 63 and 75 microm) or layer-by-layer dissection (n = 2).

Finally, quantitative analysis of intraoperative OCT scans can aid decision-making on whether to proceed with pneumatic dissection or lengthen the trephination groove, allowing the injection cannula to be inserted at the desired stromal depth.