Feasibility of Intraoperative SS-OCT for Assessing Capsular-Bag Dynamics During Cataract Surgery: Pilot Randomized Intra-Individual Comparison of Adaptive Versus Gravity-Based Fluidics

Background/Objectives: This exploratory, randomized, patient-masked, intra-individual pilot study evaluated the feasibility of intraoperative swept-source optical coherence tomography (SS-OCT) for quantifying capsular-bag dynamics during cataract surgery and explored potential differences between an adaptive fluidics system (AFS) and a gravity-based fluidics system (GFS). Methods: Twenty-seven myopic cataract patients (54 eyes) underwent bilateral phacoemulsification, with one eye randomly assigned to AFS and the fellow eye to GFS using the same phacoemulsification platform (Stellaris/Stellaris Elite, Bausch & Lomb, Rochester, NY, USA). Intraoperative SS-OCT scans were acquired at six predefined surgical stages (M1–M6) to measure anterior and posterior capsule distances relative to the corneal endothelium. Intraoperative discomfort was assessed using a visual analog scale. Results: Of 648 attempted scans, 392 (60.5%) were analyzable, confirming partial feasibility of the prototype system. At the onset of phacoemulsification with irrigation on (M2), the predefined primary endpoint, anterior-capsule distance was greater with GFS than with AFS (4.23 ± 0.58 mm vs. 3.72 ± 0.73 mm), corresponding to greater mean deepening from baseline under GFS (1.19 mm) than under AFS (0.63 mm). However, this difference was not statistically significant after adjustment for multiple comparisons. No significant inter-system differences were found at other timepoints, and overall discomfort scores were similar (p = 0.70). Conclusions: Intraoperative SS-OCT enabled real-time visualization and partial quantitative assessment of capsular-bag dynamics during cataract surgery. The observed difference at the initiation of phacoemulsification may suggest reduced anterior-capsule deepening with adaptive fluidics, but this comparison was not statistically significant after multiplicity adjustment. The 39.5% measurement failure rate underscores the need for technical refinement before routine clinical implementation.