Visual and optical performance of diffractive multifocal intraocular lenses with different haptic designs: 6 month follow-up

Prospective comparative study of tolerance to refractive errors after implantation of extended depth of focus and monofocal intraocular lenses with identical aspheric platform in Korean population

Background

To evaluate the clinical outcomes of extended depth of focus (EDOF) and monofocal intraocular lenses (IOLs) that share identical aspheric platform and compare their visual acuity tolerance to postoperative refractive errors.

Methods

This non-randomized, prospective comparative study included 120 eyes undergoing cataract surgery with implantation of either Tecnis ZCB00 IOL (Abbott Medical Optics Inc., Santa Ana, CA) (monofocal group: 60 eyes of 30 patients) or Tecnis Symfony IOL (Abbott Medical Optics, Inc.) (EDOF group: 60 eyes of 30 patients). Monocular and binocular visual outcomes, changes in refraction, defocus curve, contrast sensitivity, and perception of photic phenomena (Halo & Glare Simulator; Eyeland Design Network, Vreden, Germany) were evaluated 3 months postoperatively. To compare the refractive tolerance, each group was divided into three subgroups according to the postoperative uncorrected distance visual acuity (UDVA) and postoperative spherical equivalent (SE).

Results

In the EDOF group, the mean 3-months postoperative monocular UDVA, intermediate (UIVA), and near (UNVA) visual acuities were 0.03 ± 0.07, 0.09 ± 0.15, and 0.24 ± 0.16 logMAR, respectively. A total of 100, 96.55, and 68.97% of eyes in the EDOF group achieved binocular UDVA, UIVA, and UNVA values of 0.20 logMAR or better, respectively. In respect to refractive tolerance, the EDOF group showed higher SE values and statistically significantly better mean UDVA than the monofocal group in all subgroups, with UDVA of − 0.013 and 0.028 logMAR for EDOF and monofocal groups (p = 0.037), respectively, in the subgroup where SE was within ±0.50 D, UDVA of 0.004 and 0.048 logMAR for EDOF and monofocal groups (p = 0.046), respectively, in the subgroup where SE was within − 1.00 D, and UDVA of 0.020 and 0.083 logMAR for EDOF and monofocal groups (p = 0.026), respectively, in the subgroup where SE was more than − 1.00 D. The mean patient satisfaction scores for spectacle-free distance, intermediate, and near visual acuities were 86.0, 85.0, and 66.0, respectively.

Conclusions

The EDOF IOL provided excellent postoperative visual outcomes in far and intermediate distances, with high patient satisfaction rate. Regarding the postoperative refractive tolerance to SE, the Tecnis Symfony IOL showed better tolerance to residual postoperative refractive error than the monofocal IOL with the same material and optical platform.

Psychophysical Vision Simulation of Diffractive Bifocal and Trifocal Intraocular Lenses

PURPOSE

The visual performance of monofocal, bifocal, and trifocal intraocular lenses was evaluated by human individuals using a vision simulator device. This allowed investigation of the visual impression after cataract surgery, without the need actually to implant the lenses.

METHODS

The randomized, double-masked, three-way cross-over study was conducted on 60 healthy male and female subjects aged between 18 and 35 years. Visual acuity (Early Treatment Diabetic Retinopathy Study; ETDRS) and contrast sensitivity tests (Pelli-Robson) under different lighting conditions (luminosities from 0.14-55 cd/m², mesopic to photopic) were performed at different distances.

RESULTS

Visual acuity tests showed no difference for corrected distance visual acuity data of bi- and trifocal lens prototypes (P = 0.851), but better results for the trifocal than for the bifocal lenses at distance corrected intermediate (P = 0.021) and distance corrected near visual acuity (P = 0.044). Contrast sensitivity showed no differences between bifocal and trifocal lenses at the distant (P = 0.984) and at the near position (P = 0.925), but better results for the trifocal lens at the intermediate position (P = 0.043). Visual acuity and contrast sensitivity showed a strong dependence on luminosity (P < 0.001).

CONCLUSIONS

At all investigated distances and all lighting conditions, the trifocal lens prototype often performed better, but never worse than the bifocal lens prototype.

TRANSLATIONAL RELEVANCE

The vision simulator can fill the gap between preclinical lens development and implantation studies by providing information of the perceived vision quality after cataract surgery without implantation. This can reduce implantation risks and promotes the development of new lens concepts due to the cost effective test procedure.