| |
Intrastromal Corneal Ring (INTACS)
Intacs are the first "non-laser" surgical product approved by the U.S. Food and Drug Administration. These tiny transparent ring segments can efficiently correct mild amounts of nearsightedness (1 - 3 diopters). During a brief procedure (see below), Intacs are implanted into the periphery of the cornea. By increasing the volume in the peripheral cornea, there is a flattening in the central portion of the cornea. The Intacs procedure is highly effective, with over 80% of patients achieving 20/20 vision and over 50% of patients seeing better than 20/20! Millennium Laser Eye Center physicians were the first surgeons in the Washington area to perform the procedure. Intacs are designed to be permanent; however, the segments can be removed. Removal allows the eye to virtually return to its natural state prior to surgery. This attribute and the fact that the surgery does not involve the altering the central cornea (as with excimer lasers), make Intacs a unique technology for vision correction.
Keravision spent approximately 2 decades and 100 million dollars in basic science and clinical research to develop this product. The FDA approved Intacs in the spring of 1999. Millennium Laser Eye Center physicians were integral to the development of this product. Dr. Lemp and Dr. Clinch serve on the Data Safety Monitoring Board that reviewed all of the clinical research for Keravision. As Chairman of this committee, Dr. Lemp was a key speaker at the U.S. Food and Drug Administration panel meeting that approved this technology.
Intacs are segments of inert polymethylmethracrylate (PMMA) plastic. PMMA has bee used in ophthalmology for over 4 decades with an excellent level of biocompatibility. The procedure takes approximately 15 minutes (see below). Most patients elect to have both eyes corrected at the same time.
A small incision is made in the peripheral cornea with an ultrasonically guided diamond blade.
A small channel is developed in the peripheral cornea.
A microscopic suture (thinner than a human hair) is used to close the incision.
Visual recovery is very rapid. Patients can return to most normal activities on the same day as surgery (see post-operative instruction sheet). Patients routinely go to work on the next day. The results of the recent FDA clinical trials demonstrate long-term stability. The results at 12 months are as follows:
- Uncorrected Vision 20/40 or better was 97%
(or 98% for patients treated within the recommended prescribing range)
- Uncorrected Vision 20/20 or better was 74%
(or 78% for patients treated within the recommended prescribing range)
- Uncorrected Vision 20/16 or better was 53%
(or 56% for patients treated within the recommended prescribing range)
- Over 50% of the patients actually saw better than 20/16!
|
|
|
|
