Trifocal intraocular lenses versus bifocal intraocular lenses after cataract extraction among participants with presbyopia

Authors: Zamora-de La Cruz D, Zúñiga-Posselt K, Bartlett J, Gutierrez M, Abariga SA.

Geographical coverage: Europe 

Sector: Biomedical

Sub-sector: Treatment

Equity focus: None

Study population: People over 30 with bilateral cataracts with no pre-existing ocular pathologies or ocular surgery.

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background: Presbyopia occurs when the lens of the eyes loses its elasticity leading to loss of accommodation. The lens may also progress to develop cataract, affecting visual acuity and contrast sensitivity. One option of care for individuals with presbyopia and cataract is the use of multifocal or extended depth of focus intraocularlens (IOL) after cataract surgery. Although trifocal and bifocal IOLs are designed to restore three and two focal points respectively, trifocal lens may be preferable because it restores near, intermediate and far vision, and may also provide a greater range of useful vision and allow for greater spectacle independence in individuals with presbyopia.

Objectives: To assess the effectiveness and safety of implantation with trifocal versus bifocal IOLs during cataract surgery among participants with presbyopia.

Main findings:

Overall, authors found low certainty of evidence that compared to bifocal IOL, implantation of trifocal IOL may improve uncorrected intermediate visual acuity at one year; however, there is no evidence of a difference between trifocal and bifocal IOL for uncorrected distance visual acuity, uncorrected near visual acuity, and best-corrected visual acuity at one year.

A total of five studies were included in this review. All were conducted in Europe with a total of 175 participants. All assessed uncorrected distance visual acuity (primary outcome of the review), while some also examined secondary outcomes including uncorrected near, intermediate and best-corrected distance visual acuity, as well as contrast sensitivity. All participants had bilateral cataracts with no pre-existing ocular pathologies or ocular surgery. Mean age ranged from 58 to 64 years. All included studies were assessed as being at unclear risk of bias for most domains.

All studies compared trifocal versus bifocal IOL implantation on visual acuity outcomes measured on a logMAR scale. At one year, trifocal IOL showed no evidence of effect on uncorrected distance visual acuity (mean difference (MD) 0.00, 95% confidence interval (CI) -0.04 to 0.04; I² = 0%; two studies, 107 participants; low certainty evidence) and uncorrected near visual acuity (MD 0.01, 95% CI -0.04 to 0.06; I² = 0%; two studies, 107 participants; low certainty evidence). Trifocal IOL implantation may improve uncorrected intermediate visual acuity at one year (MD -0.16, 95% CI -0.22 to -0.10; I² = 0%; two studies, 107 participants; low certainty evidence), but showed no evidence of effect on best-corrected distance visual acuity at one year (MD 0.00, 95% CI -0.03 to 0.04; I² = 0%; two studies, 107 participants; low certainty evidence). No study reported on contrast sensitivity or quality of life at one-year follow-up. Data from one study at three months suggests that contrast sensitivity did not differ between groups under photopic conditions, but may be worse in the trifocal group in one of the four frequencies under mesopic conditions (MD -0.19, 95% CI -0.33 to -0.05; one study; I² = 0%, 25 participants; low certainty evidence). In two studies, the investigators observed that participants’ satisfaction or spectacle independence may be higher in the trifocal group at six months, although another study found no evidence of a difference in participant satisfaction or spectacle independence between groups. Adverse events reporting varied among studies. Two studies reported information on adverse events at one year. One study reported that participants showed no intraoperative or postoperative complications, while the other study reported that four eyes (11.4%) in the bifocal and three eyes (7.5%) in the trifocal group developed significant posterior capsular opacification requiring YAG capsulotomy. The certainty of the evidence was low.

Caution is advised in the use of the current evidence in clinical practice decisions, considering the limitations of the evidence. Such decisions should be based on patient preferences and provider judgement, given the variability of the results and risk of bias in the studies relevant to this topic.

Given the increasing interest in trifocal IOLs and in comparison with other presbyopic correcting options during cataract surgery, future research should compare trifocal IOL and specific bifocal IOLs that correct intermediate visual acuity in order to evaluate important outcomes such as visual acuity, contrast sensitivity, and quality of life. Future research should examine these outcomes as well as incidence of adverse events such as glare/haloes.

Methodology:

Inclusion criteria consisted of randomised controlled trials that compare trifocal and bifocal IOLs among participants 30 years or older with presbyopia undergoing cataract surgery. Included all eligible trials regardless of publication status or language of publication. Article sets of detailed criteria for primary and secondary outcomes.

Authors searched the Cochrane Central Register of Controlled Trials, Medline, EMBASE, PubMed, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. No date or language restrictions were applied. Authors searched the reference lists of the retrieved articles and the abstracts from the Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO) for the years 2005 to 2015.

Two authors independently screened studies for inclusion and extracted data of included studies using a data collection form developed by Cochrane Eyes and Vision and implemented in Covidence software (Covidence). Additionally, two authors independently assessed the risk of bias of each study using the Cochrane ‘risk-of-bias’ tool.

Authors used the Chi 2 and I² statistic to evaluate statistical heterogeneity among outcomes, with the I² statistic measuring the proportion of total variability due to heterogeneity. Publication bias was not assessed because the number of studies was less than 10.

If there was no statistical or clinical heterogeneity, or fewer than three trials contributed data to a meta-analysis, authors used a fixed-effect model to estimate intervention effects; otherwise random-effects models were used. When substantial statistical heterogeneity (I² > 60%) was detected, and the direction of treatment effects was not consistent across studies, a meta-analysis was not performed; instead, a narrative summary was presented.

Various other analyses were planned but not undertaken due to the small number of studies involved or small number of studies with particular features.

Applicability/external validity: Authors note that the findings of their study are generally in agreement with other reviews.

Geographic focus: Included studies were all conducted within Europe and there was no consideration of if/how findings may differ in a LMIC context.

Summary of quality assessment:

The procedures for identifying, including, and critically evaluating studies were extremely thorough, with no limitations based on language or publication status, and all identified studies underwent dual screening and assessment. The data analysis approach was solid, although it’s worth noting that not all planned analyses could be carried out due to the limited number of studies included. While the review’s findings are somewhat provisional, we have a high degree of confidence in these results.