Doc, I Can See!

Doctors have been able to improve the eyesight of a dozen patients with a rare inherited and previously incurable disease using an experimental form of gene therapy.

The announcement was made at a joint meeting of the American Academy of Ophthalmology and Pan-American Association of Ophthalmology in San Francisco Saturday, reports AFP.

Doctors reported that 12 patients between the ages of eight and 44 with Leber congenital amaurosis, or LCA participated in the study. LCA causes a gradual loss of sight due to degeneration of the retina, resulting in blindness usually by the age of 40.

Each of the participants treated with gene therapy in one eye, showed "improvement in retinal function," Dr. Katherine High of The Children's Hospital of Philadelphia and the Howard Hughes Medical Institute wrote in a Lancet medical journal report, also released Saturday.

Doctors found the treatment works best in younger patients, ages eight, nine and ten.

"Before, I used to ride my bike just in front of the house and now I just ride around the neighborhood with no one watching," said study participant Corey Haas, 9, according to Reuters.

To carry out the therapy, doctors designed a harmless virus to carry corrective DNA directly into the eyes of the study participants. The healthy-gene-carrying virus was injected directly into the retina. The gene, RPE65, which is mutated in about 16 percent of LCA patients, restored light-sensitive pigments in the retina at the back of the eye.

While the treatment didn't restore normal eyesight in any of the patients, benefits have persisted for almost two years and all of them had at least a 100-fold increase in pupillary light response (meaning the constriction of the pupil when exposed to light). Half of the participants recovered enough that they are no longer considered legally blind.

Up until now, there has been no treatment for LCA.

Photo courtesy of Kyle May via Flickr.