Art is Her Best Friend

Yvonne is living her dream. She is an artist, dedicated to raising awareness and funds for vision research.

Become a Community Fundraiser

Community events are a fun way for you to join the fight against blindness and fund sight saving research. Host a fundraiser in your community today!

Out-pacing vision loss

Cycle for Sight founder and co-chair, Michael Ovens, will cycle any distance or run any length to help support sight-saving research.

Meet Molly Burke, FFB Youth Ambassador

Youth Ambassador

Molly Burke is a youth ambassador for the Foundation Fighting Blindness, educating the public about living with blindness while delivering a message of hope to those living with vision impairment.

Meet Norma Bastidas, mom on a mission

Mom on a Mission

Norma is the second person in history to run 7 of the planet's most unforgiving environments on 7 continents in 1 year in support of vision research. Read her about incredible journey.

Meet Dale Turner, proof that research does work

Miracles do happen

Dale Turner is the first Canadian to receive an experimental treatment and have some sight restored by gene therapy. Dale is proof that investing in research works.

Gene Therapy Improves Vision but does not Slow Vision Loss

February 4, 2013 - Retinal degenerative diseases, such as retinitis pigmentosa and Leber congenital amaurosis, are usually caused by mutations in a single gene. In recent years, scientists have developed gene-replacement therapies as a way of replacing the functions that were lost because of these mutations (see our gene therapies fact sheet for details). Each treatment is specific to one specific genetic type of eye disease.

In the last five years, these treatments have begun to be evaluated in human trials. The initial results of these trials showed that gene therapies can improve vision. The first gene therapy to be tested, for people with Leber congenital amaurosis due to a mutation in RPE65, has now been used in more than 15 people. All of them experienced some improvements in vision.

Scientists can now study the longer-term effects of gene therapy, since it has been several years since the people in the first RPE65 trials received treatment. While the treatment appears to have produced a lasting, long-term benefit in improved function of visual cells, newly published studies show that it does not make the cells in the treated area live longer.

Loss of retinal cells causes loss of vision and thinning of the retina. In the treated RPE65 patients, treated parts of the retina lost cells at the same rate as untreated parts of the retina.

"When compared, the photoreceptor cell layers of treated and untreated eyes became thinner at a similar pace," says Dr. Samuel Jacobson, a professor at the University of Pennsylvania’s Scheie Eye Institute.

“Gene therapy improved vision but did not slow or halt the progression of cell loss,” noted his colleague, Dr. Artur Cideciyan, lead author of the study.

These results were unexpected, but the scientists report that they have now observed similar results in the dogs that were first treated with the same LCA gene therapy. The scientists are unsure why cell death continues, suggesting that perhaps abnormalities in surrounding cells continue to stress the treated cells, or perhaps some cells reach a point of no return, so that once slated for destruction they are not saved even though their functioning improves.

“These findings illustrates how complicated the effects of disease-causing gene mutations are,” says Dr. Bill Stell, Expert Scientific Advisor to the Foundation Fighting Blindness. “Much more basic research will be required, to understand how visual cells in the retina respond to the loss-of-function mutations in LCA-RPE65 and to gene replacement therapy.”

One possible solution is to use therapies in combination. Many research teams have been developing therapies that halt cell death. (See our anti-apoptosis therapies fact sheet for details). Perhaps by combining these therapies with gene therapies, the newly functioning cells can be protected.

“Slowing cell loss in different retinal degenerations has been a major research direction long before the current gene therapy trials”, says Dr. Jacobson. “Now, the two directions must converge to ensure the longevity of the beneficial visual effects in this form of LCA.”

This research was published in the Proceedings of the National Academy of Sciences.

 

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