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Trifocal IOLs can provide good uncorrected vision at near, intermediate, and far. Outcomes in a series of 30 patients show that a toric version of a trifocal IOL (AT Lisa tri 939MP, Carl Zeiss Meditec) delivers those benefits for patients with > 1 D of corneal astigmatism.
Take-home: Trifocal IOLs can provide good uncorrected vision at near, intermediate, and far. Outcomes in a series of 30 patients show that a toric version of a trifocal IOL (AT Lisa tri 939MP, Carl Zeiss Meditec) delivers those benefits for patients with > 1 D of corneal astigmatism.
Reviewed by Rui Carneiro de Freitas, MD
Braga, Portugal-A proprietary toric trifocal IOL (AT Lisa tri 939MP, Carl Zeiss Meditec) may be considered a first-line option to meet the needs of patients with significant pre-existing corneal astigmatism who are interested in refractive lensectomy for presbyopia correction, according to Rui Carneiro de Freitas, MD.
His conclusion was based on the findings of a prospective study that analyzed outcomes from 30 patients who underwent bilateral implantation with the toric trifocal IOL. Refractive results, including astigmatic correction, and uncorrected and distance corrected visual acuity (UCVA and DCVA) measured at near, intermediate, and far were excellent.
In addition, the vast majority of patients (85%) were spectacle-free at all distances, and those needing glasses only wore them for some near vision tasks. Contrast sensitivity function was within age-related normal limits at all spatial frequencies under both photopic and mesopic conditions, and it was not significantly different compared to eyes implanted with a monofocal IOL, reported Dr. Carneiro de Freitas, department of ophthalmology, Hospital Braga, Braga, Portugal.
“The [toric trifocal IOL] has a diffractive multifocal optic that distributes 50% of light for distance, 20% for intermediate, and 30% for near, and is pupil independent. As seen in our patients and as reported in studies evaluating the non-toric version of this trifocal IOL, these design features translate into a full range of functional vision with good contrast sensitivity,” he said.
“The toric version of the trifocal IOL demonstrates excellent rotational stability, resulting in accurate astigmatic correction, and allows surgeons to offer the benefits of this multifocal design to a broader patient population.”
The patients in the study were aged 50 years and older (mean 53 years), had > 1 D of corneal astigmatism (mean 1.78 D), underwent uneventful surgery, and were free of any ocular pathology that would limit visual acuity and quality with a multifocal IOL. Mean IOL power for the series was 19.8 D for sphere and 2.19 D for cylinder.
Mean expected residual cylinder was -0.16 D. At 6 months after surgery, mean sphere, cylinder, and spherical equivalent were -0.10, -0.45, and -0.35 D, respectively.
“All eyes were within 1.00 D of emmetropia and had less than 1.00 D of refractive astigmatism, while about two-thirds of eyes were within 0.5 D of emmetropia and had less than 0.50 D of refractive astigmatism,” Dr. Carnero de Freitas said.
LogMAR UCVA averaged 0.08 at near (40 - 50 cm), 0.02 at intermediate (70 - 80 cm), and 0.10 at far. DCVA was 20/25 or better in 94% of eyes and 20/25 or better at near in 80%.
“Only 15% of patients needed glasses for near and that was for reading small print or for working at close near distances of 33 to 40 cm,” Dr. Carnero de Freitas said.
“The binocular defocus curve profile was consistent with UCVA of 20/25 or better across a wide range of vergence values, from 0.0 to -2.0 D, and that explains the high spectacle independence rate in our series.”
Rotational stability was assessed at follow-up visits conducted at 1, 3, and 6 months after surgery. Mean IOL misalignment was 3.5°.
“In no eye was the IOL more than 5° off the intended axis nor did any eye have to undergo a secondary procedure for IOL repositioning,” said Dr. Carneiro de Freitas.
This article is based on a poster presented by Dr. Carneiro de Freitas and colleagues at the 2015 meeting of the American Academy of Ophthalmology. Dr. Carneiro de Freitas has no relevant financial interests to disclose.
Rui Carneiro de Freitas, MD