This morning, a patient from San Luis Obispo and a patient from Ventura both asked me about a TV show they had seen this morning featuring a new treatment for reading glasses. ABC’s Good Morning America ran a segment titled “Revolutionary New Procedure Could Replace Reading Glasses” this morning and it received quite a bit of attention. By the end of the day, another patient from Santa Barbara and a patient from Oxnard also asked me about the show. This is all for good reason: people are looking for a way to get rid of their reading glasses!
Presbyopia is the medical term for the age related loss of the ability to see up close. Presbyopia affects everyone, beginning in the early 40’s and continuing to worsen until the early 60’s. Patients become more and more dependent on their reading glasses or “cheaters” with each passing year. The underlying reason for this is that the lens of the eye, which is responsible for focusing up close, becomes stiffer with age and less able to do its job. Presbyopia is simply a part of aging. As such, there is no perfect cure for presbyopia, but there are many very good treatments.
The Good Morning America segment which aired this morning was talking about the KAMRA Intracorneal Inlay, which was recently approved by the FDA. This technique has already been in use for some time in Europe and in Asia as well as in other areas around the world. While the KAMRA is an exciting new treatment for us, it has pros and cons.
KAMRA works by insertion into the cornea of a small diameter, very thin, ring with a small opening in its center. The KAMRA inlay is placed only in the non-dominant eye. It is similar to the concept of looking through a pinhole to see more sharply. Technically, it works by a mechanism called “small aperture optics”, which is based on the principle of only letting light rays into the eye which are coming straight in and do not need focusing and clipping off those rays that do require focusing. At a practical level, this increases the range in which objects are in focus by increasing the “depth of field”. A camera does something similar when it uses a small aperture (or f-stop) to take a photo. International studies show a very high rate of success with the KAMRA inlay in increasing the range of focus to the point that patients see well up close without reading glasses, while preserving excellent distance vision. In the FDA’s review of three clinical trials, 83.5% of patients could read 20/40 up close, vision good enough to read most text in magazines and newspapers.
However, there is a trade-off in that the small aperture also reduces the total amount of light coming in. Some patients complain that the vision looks “dim” or “dark” in the eye that has the KAMRA inlay. There are other downsides to the KAMRA as well. There are ongoing concerns about corneal tissue reaction to the material the inlay is made out of. Some inlays need to be removed due to this type of tissue reaction. Other times, the tissue reaction can shift the prescription of the eye over time. The FDA’s approval of the KAMRA contains some words of caution regarding the long term safety of the device, a level of wording the FDA typically does not include. The FDA also cautions that the safety and effectiveness when using the KAMRA in conjunction with LASIK are unknown. In the words of the FDA: “the device’s safety and effectiveness in patients who have had LASIK or other refractive procedures is unknown.”
The KAMRA is the first corneal inlay to be approved by the FDA. Two other inlays are in the pipeline for approval also to treat presbyopia.
It is important to remember that while the KAMRA is a good option for patients to consider, many patients achieve excellent results without the use of a corneal inlay by using LASIK or PRK to create either monovision or blended vision in which one eye is set for distance and the other eye is set for closer up.