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 fixation.

Methods: 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 the Jikei University Hospital. The minimum follow-up duration was 3 months. Second-generation anterior segment optical coherence tomography (CASIA2; TOMEY) was used to obtain the values of tilt and decentration of the intrasclerally fixated IOL and postoperative anterior chamber depth. We investigated the relationship between refractive error and various parameters, such as IOL tilt and decentration, axial length, and keratometry. In addition to our clinical investigation, we conducted optical simulations using Zemax to evaluate the spherical shift of the IOL tilt by means of the through-focus response and change in 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 affected the refractive error. The postoperative anterior chamber depth also correlated with the refractive error (CC = 0.50; P < 0.001), as opposed to 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 also revealed a myopic shift that exponentially increased as the tilt became greater.

Conclusion: IOL tilts that are greater than 10° induce refractive error.

Keywords: CASIA2; IOL decentration; IOL tilt; Intrascleral fixation; Refractive error; Zemax.