Refractive Error Induced by Intraocular Lens Tilt After Intrascleral Intraocular Lens Fixation

Abstract Purpose To investigate the spherical shift of Intraocular lens (IOL) tilt after intrascleral fixationMethods We retrospectively reviewed the medical records of patients who underwent flanged intrascleral IOL fixation with transconjunctival 25- or 27-gauge pars plana vitrectomy at the Department of Ophthalmology of Jikei University Hospital with a minimum follow-up duration of three months. Second-generation anterior segment optical coherence tomography (CASIA2; TOMEY) was used to obtain the tilt and decentration of intrasclerally fixated IOL and postoperative anterior chamber depth. We investigated the relationship of the refractive error with these parameters, axial length, and keratometry. In addition to the clinical investigation, we performed optical simulations using the Zemax optical design program for studying the spherical shift of the IOL tilt by means of the through-focus response and change of spherical equivalent power.Results The study involved 72 eyes of 67 patients. The degree of IOL tilt was correlated with the amount of refractive error (Spearman's rank correlation coefficient [CC] = −0.32; P = 0.006). In particular, a tilt angle greater than 10° strongly influenced the refractive error. Postoperative anterior chamber depth also correlated with the refractive error (CC = 0.50; P < 0.001). The refractive error did not correlate with decentration (CC = −0.17; P = 0.15), axial length (CC = −0.08; P = 0.49), and keratometry (CC = −0.06; P =0.64). Optical simulations using the Zemax optical design program also showed a myopic shift exponentially as the tilt becomes greater. Conclusion An IOL tilt greater than 10 ° induces refractive error.