Hydrophilicity refractive index shaping has potential to alter the refractive qualities of the cornea without changing its shape.
While the technology still needs further testing and clinical trials, benchtop test results are dramatic. The power of an IOL can be reduced, or increased, up to six diopters. And once changed, the power can be changed and adjusted at least multiple times without significantly affecting the modulation transfer function of the lens.
Spherical aberration can be adjusted to customize an off the shelf IOL to the patient’s own optics. Starting with a non-toric monofocal lens, RIS makes it possible to create a spherical and/or astigmatic pattern a treatment unique to each patient.
For patients implanted with a monofocal lens who later wish they had opted for a multifocal implant, RIS may offer a solution. Benchtop tests show a monofocal lens can be converted into a multifocal lens, and vice versa. The most important optical change when converting from monofocal to multifocal functionality is a reduction in modulation transfer function because light is now being redistributed across multiple foci.
“It appears that we may also be able to reverse multifocality for people who have struggled with this technology,” Dr. Waring said. “And when going from multi- to monofocal, we see increased modulation transfer function because we are reassigning light to the same focal point.”
Changes in modulation transfer function also make it possible to adjust the amount of light allocated to different focal points within a multifocal lens. That opens the door to customized light levels for near, intermediate, and far vision, depending on patient preference and visual need, he noted. It could also be possible to change the light allocation to the different focal points sequentially to allow for neuroadaptation over several weeks or months to improve the patient’s perception of visual quality.
George O. Waring, IV, MD, FACS
E: [email protected]
This article was adapted from Dr. Waring’s presentation during Refractive Surgery Day at the 2018 meeting of the American Academy of Ophthalmology. He did not indicate financial interest in the subject matter.