AcuFocus Intracorneal Lens Generating Strong Outcomes

The AcuFocus ACI 7000 intracorneal lens (AcuFocus, Inc., Irvine, California) (Figure 1), an optical device now in US Food and Drug Administration (FDA) phase 2 clinical trials, may prove as effective as LASIK, but without the potential loss of distance vision that often accompanies other devices. This new technology could bring better vision to emmetropic presbyopes, including those who have already undergone cataract surgery and monofocal lens implantation.

The AcuFocus intracorneal lens is a small device that increases depth of focus through small diameter aperture optics. The central aperture of the device measures 1.6 mm (Figure 2), and the total diameter is 3.8 mm. After flap creation with a microkerotome or an IntraLase femtosecond laser (IntraLase Corp., Irvine, California), the AcuFocus is placed over the patient's pupil. If the lens is well centered on the pupil, it increases the depth of focus of the eye, improving intermediate and near vision while retaining good distance vision (Figure 3).

Current studies are examining two major cohorts, including 75 patients in a FDA clinical trial, of which I am involved in. Phase 3 of the trial, studying 200 to 300 patients, will most likely launch in 2007. Additional data on the intracorneal lens is also available from separate clinical trails lead by Omar Faruk Yilmaz, MD, of Istanbul, Turkey, and Michael Knorz, MD, of Mannheim, Germany. Both have generated outcomes consistent with what we are seeing in the FDA trials.

Initial data for AcuFocus intracorneal inlays is impressive—with a typical visual outcome of 20/20 at the 1-year follow-up, and J1 at intermediate and near vision, with minimal distance vision loss. We are finding, however, that there is a delayed visual recovery in relation to the procedure, which is most likely related to corneal edema. There is also the potential for mild halos—if the pupil dilates beyond the outside diameter of the device. There can be a small loss of contrast sensitivity, however, when this device is only implanted in one eye, the deficits are relatively minor compared with the assets (eg, significant increase in the depth of focus and retaining 20/20 vision in a daytime environment).

Potential complications are always possible with new procedures, and with this device, it is especially important that it is well centered on the pupil. There is mild forgiveness, but the lens does not function well if it is significantly decentered. Additionally, there is always the potential for complications whenever you raise a LASIK flap (ie, striae, slipped flap, epithelial growth, or diffuse lamellar keratitis). Throughout the AcuFocus clinical studies, the most common complications seen with LASIK are proving to be the same for this intracorneal lens.

Still, of all the devices I have seen, I am most impressed by the outcomes that the AcuFocus intracorneal lens has generated. I believe that this technology has the potential opportunity to rival myopic LASIK, which 10 years after approval, generates 1.4 million procedures per year in the United States alone. If the AcuFocus intracorneal lens continues to perform the way it has in clinical trials, it should be an appealing choice for the patient population, whom we are predicting to be aged between 45 years to 60 years.

Biovision (Mountain View, California) and Refocus Group, Inc., California) are currently using refractive index or corneal curvature change to achieve the same goal as the AcuFocus intracorneal lens. Other companies are also attempting to generate multifocal ablations, or offer lens exchange with multifocal or accommodating IOLs. All theses methods seem to work, but the optimal contest will be: Which product has the best outcome with the least amount of risk and visual side effects? The technology and opportunity is there for them all. When you look at loss in distance vision, halos, and night vision, however, the jury is still out on these devices. The attractiveness of the AcuFocus intracorneal lens procedure, for me, is that it is minimally invasive and reversible.

Richard L. Lindstrom, MD, is Founder and Attending Surgeon, Minnesota Eye Consultants, and Adjunct Professor Emeritus at the University of Minnesota, in Minneapolis. Dr. Lindstrom states that he is a consultant to Advanced Medical Optics, Inc., Bausch & Lomb, Alcon Laboratories, Inc., Eyeonics, Inc., STAAR Surgical Company, and AcuFocus, Inc. Dr. Lindstrom may be reached at +1 952 888 5800; rllindstrom@mneye.com.