Scientists are reporting development of contact lenses that could provide a continuous supply of anesthetic medication to the eyes of patients who undergo laser eye surgery -- an advance that could relieve patients of the burden of repeatedly placing drops of medicine into their eyes every few hours for several days. Their report appears in ACS' journal Langmuir.
Anuj Chauhan and colleagues explain that more than 1 million laser eye correction procedures are performed each year in the U.S. The surgery enables most patients to see clearly without eye glasses or contact lenses. The procedure known as LASIK is the most common type of laser eye surgery, but complications can develop if the patient undergoes trauma or is hit very hard at any time after the procedure. Photorefractive keratectomy (PRK) doesn't have this complication, and that's why it is preferred for athletes and those in the military. A downside to PRK, however, is a longer period of pain after surgery. To ease their pain, PRK patients place drops of several medications, including anesthetics, into their eyes every few hours, which can interfere with daily life and increase the risk of drug overdose. PRK patients receive a special "bandage contact lens" after surgery to help the outer layer of the eye heal.
The researchers tested whether anesthetics loaded onto this type of lens could release the drugs over time automatically. They found that adding vitamin E to the lenses extended the time of release of three commonly used anesthetics from just under two hours to up to an entire day -- or a few days in some instances. The vitamin E acts as a barrier, keeping the anesthetics on the eye, right where they are needed. The researchers say that, in the future, these lenses could serve as bandage contact lenses after PRK surgery while also delivering necessary pain medications.
The authors acknowledge funding from the University of Florida.