Blindness Cured. Imagine being blind and receiving a single injection that restores your vision! This sounds too good to be true but is a new reality that holds tremendous hope for people and pets in the future. Normally, most drugs are unable to reach the retina because of a natural impermeable lining, called the blood-retina barrier, that prevents most chemicals from reaching the sensitive cells of the retina and as such is a built in protective measure for the eye.
A research team from Dublin, Ireland, has successfully restored the vision of mice by temporarily weakening this retinal lining to let drug molecules injected into the blood slip through the barrier and reach the retina. A technique called RNA interference (RNAi) was used to block the production of claudin-5, a protein that normally helps make the blood-retina barrier impermeable. This method involves gene therapy using a modified virus that makes the RNA only in the presence of an tetracycline derived antibiotic called doxycycline.
One shot Approach: With this approach, patients would need only one initial injection into their eye to deliver the molecules. Then once a month they would receive the antibiotic taken by mouth, and two days later the drug to treat blindness would be injected in their blood. By then the blood-retina barrier would be sufficiently weakened to allow the drug to pass through.
Although the existing drugs to treat this condition would be too large to pass through the barrier, there are other molecules in development that are small enough to pass through into the retina. Once the barrier is removed, many of these agents could be given by mouth rather than by injection. Currently, more research is needed, however this discovery offers huge hope for restoring vision for thousands of blind pets and people.
Pets do not experience blindness due to age-related macular degeneration because their eyes lack a macula. Vision loss due to a variety of inherited and acquired ocular disorders as well as various retinal degenerative conditions are however, quite widespread in both dogs and cats and effective therapies to correct retinal degenerative problems and diseases affecting vision, including SARDS in dogs are in great demand.