Objective Depth-of-Focus Estimation from Wavefront Measurements After Implantation of an Isofocal Intraocular Lens.

Abstract

Purpose: To assess the objective depth-of-focus after implantation of isofocal intraocular lens (IOL) during cataract surgery based on VSOTF using ray tracing aberrometry.

Methods: In this prospective study, 40 eyes were implanted with the isofocal Isopure IOL (Beaver-Visitec International, Inc. [BVI], Waltham, USA). The patient assessments considered: refraction (sphere, cylinder and axis), uncorrected-distance visual acuity (UDVA), corrected-distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA, at 60 and 80 cm), distance-corrected and uncorrected near visual acuity (DCNVA and UNVA), wavefront aberrations and objective depth-of-focus using ray-tracing optical technology from several percentages of degradation on the visual Strehl ratio based on the optical transfer function (VSOTF, 90%, 80% and 60%). Patients were assessed at 3 months post-surgery.

Results: Eyes implanted with the isofocal IOL showed good outcomes in terms of refraction and visual acuity at the last follow-up visit. Specifically, half a dioptre was obtained for the spherical equivalent and about 20/20 for CDVA, about 20/25 for UIVA at 80 cm, about 20/30 for UIVA at 60 cm, and about 20/25 for DCNVA. In relation to the objective depth-of-focus computed from the wavefront analysis in our cohort, we obtained mean values of 2.12 D, 3.16 D and 4.94 D at 90%, 80% and 60% of degradation, respectively.

Conclusion: Our study shows that the isofocal IOL provides high values of objective depth-of-focus based on the VSOTF using ray tracing optical technology when implanted after cataract surgery.