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Multifocal IOLs with a trifocal diffractive optic design are available outside of the United States. They provide good visual acuity for distance, intermediate, and near and appear to provide slightly better intermediate vision than bifocal diffractive multifocal IOLs.
Take-home message: Multifocal IOLs with a trifocal diffractive optic design are available outside of the United States. They provide good visual acuity for distance, intermediate, and near and appear to provide slightly better intermediate vision than bifocal diffractive multifocal IOLs.
By Cheryl Guttman Krader; Reviewed by Rudy M.M.A. Nuijts, MD, PhD, and Soraya M.R. Jonker, MD
Maastricht, The Netherlands-If the ultimate goal of implanting a multifocal IOL (MFIOL) is to achieve spectacle independence after cataract surgery, then choosing a lens with a trifocal diffractive optic may be more advantageous than one with a bifocal diffractive design.
Such is a conclusion based on data from studies investigating visual outcomes and optical performance with trifocal diffractive MFIOLs, said Rudy M.M.A. Nuijts, MD, PhD, professor of ophthalmology, Maastricht University Medical Center, Maastricht, The Netherlands.
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Dr. Nuijts provided an overview of existing literature on trifocal MFIOLs (not commercially available in the United States), including a randomized, controlled trial his group conducted comparing trifocal and bifocal diffractive MFIOLs.
“Overall, the evidence suggests a trifocal MFIOL provides slightly better intermediate vision than a bifocal MFIOL while maintaining good near and distance vision,” Dr. Nuijts said. “Nevertheless, the incidence of optical phenomena, which is also considered a limitation of bifocal diffractive MFIOLs, appears similar with the bifocal and trifocal designs.”
The study conducted by Dr. Nuijts and colleagues is in press in the Journal of Cataract and Refractive Surgeryand is scheduled for publication in August 2015.1 It enrolled 28 patients randomly assigned to bilateral implantation with a trifocal diffractive MFIOL (FineVision MicroF, PhysIOL) or a bifocal diffractive MFIOL (AcrySof ReSTOR IQ +3, model SN6AD1; Alcon Laboratories).
Next: Further study investigations
The trifocal IOL distributes 45% of incoming light to distance, 20% to intermediate, and 35% to near (versus 59% to distance and 25.5% to near with the bifocal MFIOL) and features two superimposed bifocal patterns-one with a +1.75 D add and one with a +3.5 D add. The trifocal and bifocal MFIOLs evaluated in the study have similar negative asphericity of –0.11 and –0.10 μm, respectively (Figure 1).
No significant differences were found between the two groups of eyes in mean age or preoperative distance best-corrected visual acuity (BCVA). The refractive outcome at 6 months was also similar in the bifocal and trifocal groups (mean SE 0.11 and 0.03 D, respectively).
In binocular defocus curve testing, the trifocal group performed 0.16 logMAR better for defocus level –1 D (p < 0.01, equivalent of 100 cm reading distance) and both groups achieved 0.2 logMAR or better in the range from 0 to –3 D. There was no significant difference between the two IOL groups in mean monocular uncorrected or distance corrected visual acuity at far, intermediate, or near.
However, the rate of complete spectacle independence was higher in patients with the trifocal MFIOL implanted than in the bifocal MFIOL group (80% versus 50%).
Results from contrast sensitivity testing under photopic and mesopic conditions showed the only significant difference between groups was at 6 cycles per degree under mesopic conditions. Data from the National Eye Institute Refractive Error Quality of Life Instrument-42 found no differences between the two implant groups in the quality of vision or perceived glare and halos.
Dr. Nuijts also reviewed data from three other published studies investigating the same trifocal MFIOL in larger groups of eyes (n = 40 to 198),2-4 a cohort study including 60 eyes implanted with another aspheric trifocal MFIOL (AT LISA tri 839MP, Carl Zeiss Meditec),5 and a randomized trial comparing the latter IOL with a bifocal diffractive MFIOL from the same manufacturer (AT LISA 801, Carl Zeiss Meditec).6
Next: "Statistically significant differences"
The AT LISA tri 839MP distributes 50% of light for far, 20% for intermediate, and 30% for near. At the IOL plane it provides a near add of +3.33 D and an intermediate add of +1.66 D (Figure 2).
Dr. Nuijts reported that distance BCVA outcomes were similar for the two trifocal/one bifocal MFIOLs across all studies. Distance-corrected intermediate visual acuity for the trifocal MFIOLs ranged from 0.06 to 0.17 logMAR and was significantly better with the trifocal MFIOL than the bifocal MFIOL in the direct comparison study (0.06 versus 0.30).
Dr. Nuijts also discussed in vitro research comparing the two trifocal MFIOLs, including a laboratory bench-based study evaluating through-focus modulation transfer function curves.7
Quality of vision was simulated using different sized apertures (2, 3, 3.75, and 4.50 mm) and changing diopters of defocus representing distance (0.0 D = 4 m), intermediate (–1.5 D = 67 cm), and near vision (–3/–3.5 D = 33/29 cm).
Results showed the FineVision MicroF trifocal IOL would provide better vision at distance in eyes with larger pupils (3.75 mm) compared with the AT LISA tri 839MP.
However, the AT LISA tri 839MP had better results at intermediate and near focal points and was less dependent on pupil size.
A clinical trial comparing the FineVision MicroF and AT LISA tri 839MP IOLs in 30 patients who underwent bilateral implantation with the same lens found both trifocal MFIOLS were associated with excellent distance, intermediate, and near visual outcomes at 3 months.8
Statistically significant differences favoring the FineVision IOL were seen in analyses of distance-corrected intermediate and near visual acuity.
“Regrettably, because pupil diameter was not measured, it was not possible to assess the influence of pupil size on the in vivo results of this study,” Dr. Nuijts said.
Next: Toric, non-toric models
A toric version of the FineVision trifocal MFIOL is also available in cylinder powers ranging from 1 to 6 D in 0.75-D steps, he noted.
A small unpublished study, which has been presented by Roberto Bellucci, MD, compared visual outcomes after bilateral implantation with the non-toric and toric versions of the FineVision trifocal MFIOL. It found no differences in uncorrected or distance-corrected visual acuity at near, intermediate, or distance.
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In the defocus curve, mean visual acuity was 0.2 logMAR or better from 1 to –3 D of defocus for both IOL types (Figure 3).
1. Jonker SM, Bauer NJ, Makhotkina NY, Berendschot TT, van den Biggelaar FJ, Nuijts RM. Comparison of FineVision Micro F trifocal IOL with ReSTOR IQ +3.0 D bifocal IOL: Results of a prospective randomized clinical trial. J Cataract Refract Surg. In press.
2. Alió JL, Montalbán R, Peña-García P, Soria FA, Vega-Estrada A. Visual outcomes of a trifocal aspheric diffractive intraocular lens with microincision cataract surgery. J Refract Surg. 2013;29:756-761.
3. Cochener B, Vryghem J, Rozot P, et al. Visual and refractive outcomes after implantation of a fully diffractive trifocal lens. Clin Ophthalmol. 2012;6:1421-1427.
4. Cochener B, Vryghem J, Rozot P, et al. Clinical outcomes with a trifocal intraocular lens: a multicenter study. J Refract Surg. 2014;30:762-768.
5. Mojzis P, Peña-García P, Liehneova I, Ziak P, Alió JL. Outcomes of a new diffractive trifocal intraocular lens. J Cataract Refract Surg. 2014;40:60-69.
6. Mojzis P, Kukuckova L, Majerova K, Liehneova K, Piñero DP. Comparative analysis of the visual performance after cataract surgery with implantation of a bifocal or trifocal diffractive IOL. J Refract Surg. 2014;30:666-672.
7. Ruiz-Alcocer J, Madrid-Costa D, García-Lázaro S, Ferrer-Blasco T, Montés-Micó R. Optical performance of two new trifocal intraocular lenses: through-focus modulation transfer function and influence of pupil size. Clin Experiment Ophthalmol. 2014;42:271-276.
8. Marques EF, Ferreira TB. Comparison of visual outcomes of 2 diffractive trifocal intraocular lenses. J Cataract Refract Surg. 2015;41:354-363.
Rudy M.M.A. Nuijts, MD, PhD
This article was adapted from Dr. Nuijts’ presentation at the 2015 meeting of the American Society of Cataract and Refractive Surgery. His collaborators included Soraya M.R. Jonker, MD; Noël J.C. Bauer, MD, PhD, and Roberto Bellucci, MD. Dr. Nuijts receives grant support from PhysIOL and Alcon Laboratories and is also a consultant and speaker for Alcon Laboratories.
Soraya M.R. Jonker, MD
Dr. Jonker did not indicate any financial interest in the subject matter.