Can Accommodating IOLs Fuel Demand?
For nearly two decades, “presbyopia-correcting” intraocular lenses (IOLs) have been available to post-cataract surgery patients, but for a variety of reasons they have garnered only modest interest.
According to Market Scope, presbyopia-correcting lenses only account for 2.4% of total IOLs implanted globally in 2014. Moreover, use of these IOLs has grown only 6% per year since 2010.
However, industry hasn’t given up. New presbyopia-correcting IOLs, including accommodating and toric accommodating designs, are being developed with an eye toward expanding the stunted market.
Market Scope forecasts nearly 11% growth in presbyopia-correcting IOLs through the end of 2016 as new options become available.
These aren’t easy challenges. Presbyopia correction can be approached in a number of ways. Multifocal IOLs incorporate discrete optical elements into the lens to offer both near and distance vision. This design strategy trades off some of the benefits of seeing through a single zone in order to have a greater range of focus.
However there are drawbacks. While many multifocal patients can read without glasses, their distance vision may not be as sharp as it might be with a monofocal IOL. Multifocal patients often complain of seeing glare and halos, especially at night, in the first few months after surgery. As a result, considerable time and money are being invested in the development of IOLs that reduce or eliminate the problems of current multifocals.
One approach, accommodating IOLs, tackle the problem differently. Instead of placing multiple focusing elements in a single fixed lens, most accommodating lenses change focus by utilizing a single optical element that moves like a camera lens or alters shape. Typically, the eye’s “focusing” or ciliary muscle powers the movement or shape change. Currently approved accommodating designs cause less loss of contrast sensitivity and are less likely than multifocal IOLs to produce glare and halos.
A drawback to most mechanical accommodating IOLs is that the ciliary muscle may not be strong enough to power the lens to provide an in-focus image at every distance. As a result, currently approved accommodating lenses typically can’t provide a full range of vision. IOL developers continue to investigate new accommodating designs in hopes of gaining enough accommodation to provide sharp vision at all distances.
A Review of the Current Pipeline
Crystalens® and Trulign® Toric (both by Bausch + Lomb) are currently the only FDA-approved IOLs that can be described as accommodating. (Very similar in design, the FDA allows Crystalens to be called “accommodating” but only allows Trulign to be described as offering “a broader range of vision.”) Both are mechanical IOLs because accommodation is powered by action of the ciliary muscle as opposed to, for example, electricity.
In clinical studies, Crystalens and Trulign have been shown to provide about 1 diopter of accommodation. That is not enough to give patients good distance and near vision, although it may suffice for good distance and intermediate vision. Some critics claim that a single-optic IOL can’t possibly move enough with the eye to produce a substantial change in power.
The FDA approved the original version of Crystalens in 2003, at which time it was developed and marketed by a startup company called eyeonics. Bausch + Lomb acquired Crystalens in early 2008; and in June of that year, the FDA approved a “high-definition” version of Crystalens, which incorporates an optic designed for better near vision. In 2010, Bausch + Lomb introduced the Crystalens Aspheric, which has an optical design that gives it improved contrast sensitivity and reduces higher order aberrations. In May 2013, the FDA approved a toric version of the lens, called Trulign. (Toric designs correct astigmatism.)
Synchrony (developed by Visiogen) was a mechanical accommodating IOL with two lenses that moved closer or farther apart to change focus. When Abbott Medical Optics (AMO) acquired Visogen for $400 million in 2009, Synchrony had just received CE marking in Europe. However, the lens got stalled in the FDA approval process for three years, and eventually AMO discontinued it.
Sapphire Autofocal (Elenza, Inc.) is billed as the first “electro-active” accommodating IOL. Accommodation occurs by means of a liquid crystal optic that changes power in response to an electronic signal. The lens contains a rechargeable battery and changes focus based on physiological triggers.
After two years of development in 2010, Elenza approached Alcon for financing. Over the next 11 months, Alcon conducted a due-diligence review and made a first-round investment of several million dollars. In April 2011, Alcon was acquired by Swiss-based Novartis. The company declined to invest in a subsequent round, and Elenza has claimed Novartis is attempting to “exploit the technologies invented by Elenza and to capture for itself 100 percent of the anticipated revenues from the commercialization of Elenza’s technologies.” The matter is in litigation.
Tetraflex (Lenstec) is a mechanical accommodating IOL with a single, square-edged, acrylic optic that flexes to provide accommodation. It is undergoing US clinical trials.
The Tek-Clear IOL (Tekia) is another square-edged, single-optic mechanical accommodating IOL that moves in response to natural movement of the ciliary muscle. It received a CE mark in 2006, but is not yet FDA-approved.
NuLens (NuLens Ltd.) is a single-optic, mechanical accommodating IOL designed to provide up to 10 D of accommodation. NuLens works like a piston: eye muscles push against a silicone gel lens, which changes shape to provide focus at different distances. Early research has been conducted in Europe.
The FluidVision accommodating IOL (PowerVision) uses fluid-based mechanics to change its shape in response to the movement of the ciliary muscle. This dual-optic lens is undergoing clinical trials in the US.
Lumina (Akkolens) is a dual-optic, mechanical accommodating lens designed for placement in the sulcus, as sulcus placement may be less affected by fibrosis than placement in the capsular bag. Clinical trials have been completed in Europe, and Akkolens is anticipating a CE mark.
Freeman W. Expanding PC-IOL Options Expected to Fuel Demand Among Patients. Market Scope. July 17, 2105; 19(7): 1-2.