Researchers are developing a new contact lens designed to provide a continuous supply of anesthetic medication to the eye for patients recovering from laser eye surgery.

This new technology uses vitamin E to help release drugs automatically over time, thus eliminating the need for patients to repeatedly use medicine drops. Tests show that the time release of three commonly used anesthetics was extended from slightly less than two hours to up to seven days in some instances.

According to Anuj Chauhan, Ph.D., and his colleagues, the medication-releasing contact lenses may be used for LASIK and photorefractive keratectomy (PRK).

While LASIK is the most common type of laser eye surgery, complications can and do occur if the patient undergoes trauma, such as a hard hit to the face. PRK patients, on the other hand, face a long and painful recovery period where they must wear a bandage contact lens after surgery and place drops of several medications—including anesthetics—into their eyes every few hours. This routine interferes with daily life and increases the risk of drug overdose.

To that end, Dr. Chauhan and his colleagues tested whether anesthetics loaded on this new contact lens could release drugs automatically over time. They found that vitamin E acts as a barrier to keep the anesthetic in place on the eye. In the future, the researchers say these lenses could be used as bandage contact lenses post-PRK surgery.

Peng CC, Burke MT, Chauhan A. Transport of topical anesthetics in vitamin e loaded silicone hydrogel contact lenses. Langmuir. 2012 Jan 17;28(2):1478-87. Epub 2011 Dec 22.