What did we want to find out?
We wanted to find out whether there is a difference in effectiveness and safety of implantation of a lens that contains three regions that correct for distance, intermediate, and near vision (trifocal) into the eyes during cataract surgery compared to a lens that contains two regions that correct for distance and near vision (bifocal) in people with cataract.
We found 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 with those who had received bifocal lens, but we have little confidence in the evidence. There was no evidence of a difference between trifocal and bifocal lenses for uncorrected distance visual acuity, uncorrected near visual acuity, and best-corrected distance visual acuity at one year. The effects of trifocal and bifocal lenses on quality of life and the ability to distinguish between fine increments of light and dark (contrast sensitivity) remain uncertain.
What is presbyopia, and how is it treated?
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 dependence on eye glasses use after cataract surgery.
What did we do?
We searched for studies that examined trifocal versus bifocal lenses in people with presbyopia. We compared and summarized the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found seven relevant studies conducted in Europe and Turkey with a total of 331 people with presbyopia.
We found that the implantation of trifocal lens at the time of cataract surgery may improve intermediate visual acuity at one year. We found no evidence of a difference between trifocal and bifocal lens in uncorrected distance visual acuity, uncorrected near visual acuity, and best-corrected distance visual acuity at one year. It is uncertain whether trifocal compared with bifocal lens implantation has any effect on quality of life or contrast sensitivity.
What are the limitations of the evidence?
We have little confidence in the evidence because we were unclear about how studies were conducted, and we found only small number of relevant studies.
How up-to-date is this review?
We searched for studies published up to 31 March 2022.
We found low-certainty of evidence that compared with bifocal IOL, implantation of trifocal IOL may improve uncorrected intermediate visual acuity at one year. However, there was 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, quality of life, and vision-related adverse effects.
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.
To assess the effectiveness and safety of implantation with trifocal versus bifocal IOLs during cataract surgery among people with presbyopia.
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2022, Issue 3); 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 31 March 2022.
We included randomized controlled trials that compared trifocal and bifocal IOLs among participants 30 years of age or older with presbyopia undergoing cataract surgery.
We used standard Cochrane methodology and graded the certainty of the body of evidence according to the GRADE classification.
We identified seven studies conducted in Europe and Turkey with a total of 331 participants. All included studies assessed visual acuity using a logarithm of the minimum angle of resolution (LogMAR chart). Of them, six (86%) studies assessed uncorrected distance visual acuity (the primary outcome of this review). Some studies also examined our 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. Participants' mean age ranged from 55 to 74 years. Three studies reported on gender of participants, and they were mostly women. We assessed all of 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.
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). One study examined vision-related quality of life using the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) at six months, and suggested no evidence of a difference between trifocal and bifocal IOLs (MD 1.41, 95% CI −1.78 to 4.60; 1 study, 40 participants; low-certainty evidence).
Adverse events reporting varied among studies. Of five studies reporting information on adverse events, two studies observed no intraoperative and postoperative complications or no posterior capsular opacification at six months. One study reported that glare and halos were similar to the preoperative measurements. One study reported that 4 (20%) and 10 (50%) participants had glare complaints at 6 months in trifocal and bifocal group, respectively (risk ratio 0.40, 95% CI 0.15 to 1.07; 40 participants). One study reported that four eyes (11.4%) in the bifocal group and three eyes (7.5%) in the trifocal group developed significant posterior capsular opacification requiring YAG capsulotomy at one year. The certainty of the evidence for adverse events was low.