Research shows small-aperture IOL is bringing stability into focus

Sep 09, 2019



New offering is extending patients' depth of focus with minimal drawbacks 

Reviewed by John Vukich, MD

A small-aperture IOL remains stable after two years, extending patients’ depth of focus with few dysphotopsias, researchers say. Subjects implanted with the AcuFocus IC-8 IOL, which works on the principle of pinhole optics, maintained mean monocular logMAR far visual acuity of 0.11 ± 0.13, intermediate visual acuity of 0.08 ± 0.15 and near visual acuity of 0.20 ± 0.15 at a mean follow-up of 29.9 months.

“The drawbacks are minimal,” said John Vukich, MD, who practices at Davis Duehr Dean in Madison, WI. “Patient satisfaction has been extraordinary.” Dr. Vukich presented the two-year results of aEuropean post-market study along with highlights of the advantages of the IC-8 over toric IOLs in correcting astigmatism.

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The IC-8 is a one-piece hydrophobic acrylic posterior chamber IOL with an optic that contains an embedded mask with a 1.36-mm central aperture. The dimensions of the mask and aperture contained within the optic are based on the AcuFocus Kamra corneal inlay, with a smaller diameter and flatter radius of curvature to account for its more posterior placement within the eye.

It is CE Marked and currently available in some European and Asia Pacific markets. Phase III clinical trials are nearing completion in the United States.

To evaluate the long-term effectiveness of the IC-8, Dr. Vukich and colleagues reviewed the charts of 64 patients presenting at a single visit after implantation of the IC-8 in one eye and an aspheric monofocal IOL in the other. The target refractions were -0.75 D in the IC-8 eye and plano in the monofocal eye.

The patients achieved mean binocular logMAR far visual acuity of -0.01 ± 0.10, intermediate visual acuity of 0.04 ± 0.14 and near visual acuity of 0.18 ± 0.15. That compared with -0.04 ± 0.11, 0.05 ± 0.13 and 0.17 ± 0.14 at six months.

“These results were immediate in their optical benefit and durable; there seemed to be no significant drop off,” said Dr. Vukich, adding the small-aperture lens offers advantages in correcting corneal astigmatism.

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Fewer than 5% of patients opt for toric IOLs, even though 52.6% present with more than 0.75 D of cylinder prior to cataract surgery.

Dr. Vukich also noted that axis shifts can induce misalignment, and misalignment and postimplantation rotation reduces the effectiveness of toric lenses. He cited reports that every degree of rotation reduces effectiveness by 3.3%.

By contrast, Dr. Vukich said, the IC-8 remains 100% effective, even with 30 degrees of rotation. It can tolerate up to 1.50 D of corneal astigmatism. The small-aperture design is symmetrical, eliminating the need for axis alignment.

In the post-market study, patients with less than 0.75 D of astigmatism achieved mean logMAR far visual acuity of 0.00, intermediate visual acuity of 0.05 and near visual acuity of 0.18.

Those with 0.76 D to 1.50 D achieved -0.01 for distance, 0.05 for intermediate and 0.22 for near. For those with greater than 1.50 D, those number were 0.06, 0.27 and 0.42 respectively.

The IC-8 can also compensate for many corneal irregularities from injury or previous corneal surgery, he said.

“This is a lens that is forgiving,” said Dr. Vukich. “You do not have to worry about small amounts of astigmatism causing problems. It gives you a large landing zone, a large range where you get a good distance outcome for quality of vision.”

The IC-8 will compete against multifocal lenses that also offer a solution for patients who would like to address their presbyopia at the same time as their cataracts.

Related: Toric, presbyopia-correcting IOLs good ptions for glaucoma patients 

The multifocal lenses now on the market provide good functional vision, but with the drawbacks of reduced contrast, visual disturbances and noncontinuous range of vision. The IC-8 offers advantages over these lenses because the aperture itself creates the depth of focus, said Dr. Vukich.

“From that standpoint it is a very smooth transition,” he said. “It’s a seamless change in depth of focus from far to near.”

Read more by Laird Harrison
 

John Vukich, MD
P: 608/282-2000
This article is adapted from Dr. Vukich's presentations at American Society of Cataract and Refractive Surgery 2019. Dr. Vukich is a consultant to AcuFocus, Avedro, Clerio, Vision, Johnson & Johnson, STAAR Surgical, and Zeiss. 

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