What is the best solution for those with genetic disorders that lead to blindness? As an engineer, I tend to think that the answer should lie in some sort of novel device which solves the problem. For example, if the retina is destroyed, why not ‘plug’ an array of light detecting electrodes in it’s place and wire those connections to the cortex? This has been tried, and the results are less than stellar. The most elegant solution would be to repair the tissue, rather than work around it. Thanks to frontier research in gene therapy, this treatment will, I think, one day win out over medical devices. After all, who needs an artificial heart if their doctor can 3D print a new one for them?
Recently, gene therapy has been used to improve retinal sensitivity in persons with a type of childhood blindness known as Leber congenital amaurosis, or LCA. LCA is a group of degenerative diseases of the retina and it is the most common cause of congenital blindness in children. A type of LCA is caused by a mutation in the RPE65 gene. This particular gene is responsible for the processing of vitamin A so that photoreceptor cells do their job. When this gene isn’t working, blindness occurs. (Side note: There are 500 genes have been identified that affect the eye and visual system.)
The results were impressive. There was significant improvement in both day and night vision in the patients. Yet, the gene therapy did not affect vision lost due to deterioration of photoreceptor cells. Still, this therapy offers an option to those with LCA that was not previous available.
In a separate study, researchers looked into how the brains of those who received this gene therapy were affected by regaining their vision. Through the use of MRI data, researchers found that restoring cells in the eye lead to the restoring brain pathways involved in vision-an important link.
“It’s an elegant demonstration that these visual processing pathways can be restored even long after the period when it was thought there would be a loss of plasticity,” said Jean Bennett, MD, PhD, professor of ophthalmology and cell biology at the University of Pennsylvania’s Perelman School of Medicine, the director of the Center for Advanced Retinal and Ophthalmic Therapeutics and one of the researchers in this study.
While these studies concern one particular type of blindness, they both show that blindness isn’t always going to be a case of diminished or worsening vision. As research in genetics, vision and the brain continue, treatments that were previously unthinkable will be developed that will lead to a brighter future for those with diseases of the eye and vision disorders.