Trifocal versus bifocal lenses implantation after cataract surgery

What was the aim of this review?
The aim of this Cochrane Review was to examine whether implantation of a lens that contains three regions that correct for distance, intermediate, and near vision (trifocal) into the eyes during cataract surgery differs from a lens that contains two regions that correct for distance and near vision (bifocal), with regard to effectiveness and safety among participants with cataract.

Key messages
There was low-certainty evidence that people who receive trifocal lens after their cataract surgery may experience improvement in uncorrected intermediate sharpness of vision (visual acuity) at one year compared to those who had received bifocal lens. However, there is no evidence of a difference between trifocal and bifocal intraocular lenses for uncorrected distance visual acuity, uncorrected near visual acuity, and best-corrected distance visual acuity at one year. Their effect on quality of life and the ability to distinguish between fine increments of light and dark (contrast sensitivity) remains uncertain.

What was studied in this review?
Presbyopia is an age-related condition of the lens of the eye that causes a gradual loss of the ability to focus on nearby objects. Further age-related lens changes may lead to loss of clarity of the lens (cataract) causing loss of visual acuity and contrast sensitivity. Lenses with three or two regions (trifocal or bifocal respectively) are a new technology intended to decrease the dependence on eye glasses use after cataract surgery.

What are the main results of this review?
This review included five studies conducted in Europe with a total of 175 participants.

We found that the implantation of trifocal lens at the time of cataract surgery may improve intermediate visual acuity at one year; the certainty of the evidence was low. Comparison of trifocal versus bifocal lens revealed no evidence of a difference with respect to uncorrected distance visual acuity, uncorrected near visual acuity, and best-corrected distance visual acuity at one year; the certainty of the evidence was low. It is uncertain whether trifocal compared to bifocal lens implantation has any effect on quality of life and contrast sensitivity.

How up-to-date is this review?
We searched for studies published up to 26 September 2019.

Authors' conclusions: 

There is 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. Future research should include the comparison of both trifocal IOL and specific bifocal IOLs that correct intermediate visual acuity to evaluate important outcomes such as contrast sensitivity and quality of life.

Read the full abstract...
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 intraocular lens (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.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2019, Issue 9); Ovid MEDLINE; Embase.com; PubMed; ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 26 September 2019. We 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.

Selection criteria: 

We included randomized controlled trials that compared trifocal and bifocal IOLs among participants 30 years or older with presbyopia undergoing cataract surgery.

Data collection and analysis: 

We used standard Cochrane methodology.

Main results: 

We identified five studies conducted in Europe with a total of 175 participants. All five studies assessed uncorrected distance visual acuity (primary outcome of the review), while some also examined our secondary outcomes including uncorrected near, intermediate, and best-corrected distance visual acuity, as well as contrast sensitivity.

Study characteristics

All participants had bilateral cataracts with no pre-existing ocular pathologies or ocular surgery. Participants' mean age ranged from 58 to 64 years. Only one study reported on gender of participants, and they were mostly women. We assessed all the included studies as being at unclear risk of bias for most domains. Two studies received financial support from manufacturers of lenses evaluated in this review, and at least one author of another study reported receiving payments for delivering lectures with lens manufacturers.

Findings

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%; 2 studies, 107 participants; low-certainty evidence) and uncorrected near visual acuity (MD 0.01, 95% CI −0.04 to 0.06; I2 = 0%; 2 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%; 2 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%; 2 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 suggest 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; 1 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

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.

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