Presbyopia Treatment With Intracorneal Inlays
Hello. I'm Dr. Roger Steinert, Chair of Ophthalmology and Director of the Gavin Herbert Eye Institute at the University of California, Irvine. I just returned from the World Ophthalmology Congress, held this year in Tokyo, Japan, and had the opportunity to participate in several sessions on presbyopia treatments with intracorneal inlays.
The inlay that has received the most discussion recently has been the AcuFocus (Irvine, California) KAMRA™ inlay. This is hopefully going to the US Food and Drug Administration (FDA) panel later this spring, and we are all hoping for a favorable outcome from the panel meeting. The person with the most experience with the AcuFocus is Dr. Minoru Tomita, who works in Japan and has performed about 10,000 AcuFocus KAMRA inlays.
For those of you who are not familiar with that device, it is a pinhole device that is implanted in the cornea, typically at about a 200-micron depth. The aperture in the center is 1.6 mm, and there is a fine skirt that goes around and creates the pinhole effect. The skirt has laser-created micropores that are stacked so that they can transmit nutrients but still effectively block light. This is put in one eye, typically the nondominant eye, and because of its pinhole qualities it is able to improve near vision and should not have any negative impact on distance vision.
Dr. Tomita's presentations back up the fact that the vast majority of patients do extremely well with the inlay. The strongest reading occurs in the middle-aged population. It does tend to diminish a little bit in the group of patients over the age of 60 years, but under the age of 60 years, where there is still presumably a little bit of accommodation left, the performance, on average, is quite good.
If a patient does not like the inlay, it can be removed, and typically there is a return to the preoperative vision without any difficulty. Centration is relatively important, but a partner presentation demonstrated that whether it's centered on the Purkinje reflex or centered on the pupil (unless it's a very eccentric pupil) does not seem to matter. Basically, there was about a 0.4-mm leeway in terms of centration without starting to have any deleterious effect. Some patients have had glare issues, and some have complained of difficulty with nighttime vision.
The other major set of presentations was from ReVision Optics (Lake Forest, California), with their Raindrop® intracorneal inlay.[2,3,4] I am disclosing that I am the medical monitor for the US studies (under the auspices of the FDA) for this device. Several of us -- Enrique Barragan, myself, and Dr. Beatrice Cochener -- presented our current results. The US FDA trials are well along in phase 3. The FDA requires multiyear follow-up on such devices, so it will be a little while before this is ready for submission to the panel.
With the current device and the current pharmacologic regimen, the results have been very strong -- stronger, in fact, than we would have had reason to expect, in the sense that not only are patients reliably achieving near vision, most of them are at the J1 level and almost everybody is at J2 or better. Furthermore, they gain the equivalent amount of intermediate vision and typically only drop down to about 20/25 in terms of distance vision. The tolerance of this device has been exceptional.
Currently in the US trial, the device is put in the nondominant eye. It is a hydrogel material that is 2 mm in diameter, but it functions -- and this is part of the key to the optical success -- by creating a shape that has been termed "profocal." It is a derivative of "prolate," but it is a centrally prolate cornea in a sense. The key -- and you can see this on high-resolution optical coherence tomography -- is the epithelial remodeling that occurs, which creates a transition zone that extends out to almost 4 mm. Patients gain distance, intermediate and near. Whether they are a little hyperopic or a little myopic doesn't seem to matter. The effective range of distance vision correction is anywhere from -0.5 to +1.25, and the outcomes are virtually identical. Age has also been investigated, and we do not see any difference in terms of the response of the patients to the inlay. More studies will be available and more data will be reported, but right now we have the core data from the first 200 patients to make it through 1 year in the US FDA trials.
Many exciting things are coming along for presbyopia. We all know about the intraocular lens-based treatments now, and we hope for even further improvement in those lenses.
The World Ophthalmology Congress was very heavily attended. Tokyo is a fascinating city, and it was wonderful to have the opportunity to interact with international colleagues and hear updates on their results. On behalf of Medscape, I'm Dr. Roger Steinert. Thank you for listening.
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Cite this: Advances in Presbyopia Correction - Medscape - Apr 18, 2014.