Blind Spot

When light falls on the retina at the back of our eyes, images from the outside world are quickly turned into signals bound for the brain. But Best disease can disrupt the carefully ordered layers of retinal cells, a process called macular degeneration, which leads to blindness. To investigate the condition, scientists stared deep into a dog’s eyes. On the left, a mutated form of a gene called BEST1 prevents layers of photoreceptors from attaching to retinal pigment cells creating a dark hole or 'lesion'. Using gene therapy to 'infect' the eye with a new healthy form of BEST1, scientists restored the dog’s vision – five years later man’s best friend is still free of the canine form of Best disease. Similar therapies could help human retinal layers to stitch back together, restoring vision for adult sufferers while avoiding children inheriting the condition from developing symptoms.

Written by John Ankers

• Image from the University of Pennsylvania
• School of Veterinary Medicine, and Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, USA
• Image copyright held by the original authors
• Research published in PNAS, March 2018