Contribution Factors of Effective Lens Position, Tilt, and Decentration during Flanged Scleral Fixation of Intraocular Lens: A Model Eye Study

Abstract

Purpose: We aimed to elucidate the factors related to effective lens position (ELP), tilt, and decentration of scleral fixed intraocular lenses (IOLs) with a flanged haptic technique in an artificial eye model using anterior segment optical coherence tomography (AS-OCT). Methods: Two bent 27-gauge needles were passed through a 1.0- or 2.0-mm scleral tunnel, 2.0 mm posterior to the limbus and 180° apart. Both haptics of a 3-piece IOL were docked with guide needles and externalized. Factors related to the IOL position were analyzed using AS-OCT and a stereomicroscope. Results: The 1.0-mm scleral tunnel induced a significantly longer ELP than the 2.0-mm tunnel and suture fixation (p<0.05 and p<0.01, respectively). Discrepancy in scleral tunnel length induced higher decentration of the optic to the opposite side of the haptic-embedded shorter tunnel and tilt perpendicular to the fixed axis than that in the scleral tunnel of the same length (p<0.001 and p<0.05, respectively). If the scleral fixation points of both haptics are not exactly 180° apart, the IOL may become decentered and tilted (p<0.01 and p<0.05, respectively). Conclusion: In the flanged haptic technique, the length, balance, and position of both scleral tunnels determine IOL ELP, tilt, and decentration.