Biomechanical assessment of intraocular lens stability and position based on suture and inlet variations in the Canabrava double-flanged technique

PURPOSE: To evaluate how variations in suture type, suture length, and scleral outlet angle affect intraocular lens (IOL) positioning and fixation stability in the Canabrava technique, given ongoing concerns such as iris chafing and the lack of prior quantitative assessment. SETTING: Laboratory-based experimental study using 3D-printed model eyes. DESIGN: Experimental study using 3D-printed ocular models with controlled variation of fixation parameters. METHODS: Using 3D-printed eye models, IOL fixation was performed with the Canabrava technique using Artis PLE IOLs. Suture types (5-0 Prolene, 6-0 Prolene, 6-0 Pronova), suture lengths (8 mm, 10 mm), and scleral outlet angles (30 degrees, 45 degrees) were systematically varied. IOL tilt and optic-haptic distance were measured using ImageJ. Fixation strength was assessed using a universal testing machine to measure the force required to produce a 2.5 mm linear displacement of IOL. RESULTS: IOL tilt was not significantly affected by suture type but increased with longer suture length (10.0 mm vs 8.0 mm) for both 5-0 and 6-0 Prolene. Optic-haptic distance showed minimal variation, with differences noted only in the 5-0 Prolene and 6-0 Pronova groups at 8.0 mm. Scleral outlet angle also had no significant impact on optic-haptic distance. Displacement force did not differ significantly between suture types. CONCLUSIONS: Caution is advised in patients with a predisposition to iris chafing because the risk may persist regardless of fixation parameters.