Diffractive multifocal intraocular lens compared to pseudo-accommodative intraocular lens implant for unilateral cataracts in pre-presbyopic patients

Visual satisfaction and spectacle independence with monofocal intraocular lens with enhanced intermediate vision and trifocal intraocular lenses in the prepresbyopic age group patients with cataracts

AIM

This aims to study visual satisfaction and spectacle independence in prepresbyopic age patients with cataracts after the implantation of either monofocal intraocular lens (IOL) with enhanced intermediate vision or trifocal IOL.

SETTING

Private practice.

MATERIALS AND METHODS

This prospective, observational case study was conducted on patients in the prepresbyopic age group with cataracts. Patients were allocated to one of the two groups. Thirteen patients (26 eyes) received monofocal IOL with enhanced intermediate vision (intermediate vision group), and 12 patients (24 eyes) received diffractive multifocal IOLs (trifocal group). Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity, Uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) values, defocus curves, and contrast sensitivities (CS) of the two groups were compared 3 months' postsurgery. Their spectacle independence and visual satisfaction were also assessed.

RESULTS

The study patients were aged 35-45 years and comprised 14 males and 11 females. No significant difference was observed in UDVA (intermediate vision group: 0.02 ± 0.01, trifocal group: 0.02 ± 0.01; P = 0.22) and UIVA (intermediate vision group: 0.20 ± 0.10, trifocal group: 0.19 ± 0.10; P = 0.12). However, a statistically significant difference was observed between the groups in terms of UNVA (intermediate vision group: 0.32 ± 0.10, trifocal group: 0.80 ± 0.10; P = 0.01). The mean CS in monofocal IOL with enhanced intermediate vision and trifocal groups were 1.577 ± 0.3 and 1.550 ± 0.2, respectively (P = 0.40). None of the patients experienced photic phenomena. In total, 10 of 13 patients in the monofocal IOL with enhanced intermediate vision group required spectacle correction for near visual acuity in the range of +1.00 to +2.00 D.

CONCLUSION

This study found that there was no significant difference in distance and intermediate vision between the two groups. However, the trifocal group had better uncorrected near vision compared to the monofocal group that had enhanced intermediate vision. The conclusion is that using trifocal IOLs for both eyes provided complete independence from wearing glasses. In addition, no visual disturbances were observed after implanting the new-generation trifocal IOLs.

Monovision Versus Multifocality for Presbyopia: Systematic Review and Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

Refractive surgery in presbyopia tends to achieve spectacle independence with minimal optical disturbances. We compared monovision to multifocality procedures regarding these outcomes.

METHODS

We conducted a systematic review of published (till November 21, 2016) randomized controlled trials (RCTs) comparing any monovision to any multifocality method or comparing different monovision/multifocality methods to each other that enabled direct or indirect comparisons between particular monovision and particular multifocality procedures in presbyopic patients undergoing cataract-related or unrelated surgery in respect to spectacle independence, unaided binocular visual acuity (VA), contrast sensitivity (CS), and adverse events.

RESULTS

Three trials comparing monovision (monofocal lenses, LASIK) to multifocal intraocular lenses (MFIOLs; Isert refractive or Tecnis diffractive) and 6 comparing other MFIOLs to Tecnis were included (1-12 months duration). Spectacle independence. All reporting trials were of sufficient quality. Directly, pseudophakic monovision was inferior to Isert (1 trial, N = 75, RR = 0.49, 95% CI 0.28-0.80) and Tecnis (1 trial, N = 211, RR = 0.36, 95% CI 0.25-0.52) in cataract patients, and LASIK was comparable to Tecnis (1 trial, N = 100, RR = 0.93, 0.78-1.10) in refractive surgery. In network meta-regression (6 trials, 14 arms) pseudophakic monovision in cataract patients was inferior to Tecnis. Indirect data suggest also that it is inferior (ReZoom refractive, TwinSet diffractive) or tends to be inferior (Array refractive) to other MFIOLs. LASIK was comparable to Tecnis in refractive surgery. Indirect data suggest also that it tends to superiority vs. ReZoom or Array refractive MFIOLs. Adverse events. No pooling was possible (heterogeneity of assessment and reporting). One quality direct RCT indicated less glare/dazzle with pseudophakic monovision vs. Tecnis in cataract patients. Unaided VA and CS data were burdened with heterogeneity (assessment, reporting) and insufficient quality.

CONCLUSIONS

Randomized comparisons of monovision to multifocality are scarce. Existing estimates regarding spectacle independence (imprecision, indirectness) and particularly regarding unaided VA and CS (assessment/reporting heterogeneity, bias, imprecision, indirectness) are burdened with uncertainty. Dysphotopsia is less common with monovision, but estimate uncertainty is high (bias, imprecision).

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.