Side view of a retina as captured by SD-OCT. The EZ Width is the yellow line extending between the arrows. The patient has advanced RP with significant loss of peripheral vision.
A key to gaining regulatory approval for an emerging retinal-disease therapy is quickly and accurately demonstrating that it saves or restores vision in a clinical trial. Though the goal sounds simple enough, proving that a potential treatment is working is actually difficult. That’s because commonly used measures of visual function — including visual acuity and visual fields — are not always reliable for evaluating vision changes in many people with inherited retinal conditions.
For example, visual acuity can remain stable for someone with retinitis pigmentosa (RP) for decades. While visual fields for people with RP contract over time, measuring the changes objectively is challenging; results for a given patient can vary significantly, even for the same patient on the same day.
No, people with inherited retinal diseases don’t have to adopt new names or personas, or go into witness protection programs, to save their vision. But by changing the identity of cells in the retina — namely rods — researchers may someday be able to slow or halt vision loss for those with retinitis pigmentosa (RP) and other related conditions.
While the innovative therapeutic approach is not ready to be tested in humans, a research team led by Tom Reh, PhD, University of Washington, and Sheng Ding, PhD, University of California, San Francisco, accomplished the feat in mice with RP. The investigators treated rods in the mice with a compound known as photoregulin1 (PR1) that blocked a gene involved in rod development called Nr2e3. That, in turn, reduced the expression (activity) of other rod-associated genes, making the rods less rod-like and more like cones. Doing so stopped retinal degeneration, preserving both rods and cones. Rods and cones are important, because they’re the cells that make vision possible. Results of the PR1 study were published online in the journal Investigative Ophthalmology & Visual Science.
The Foundation Fighting Blindness annual report, released this week, details another groundbreaking year in which Foundation-funded studies made great strides across the continuum of research that will one day cure blindness caused by retinal degenerative disease. That work included harnessing the power of gene and stem-cell therapies, partnering with pharmaceutical companies to develop new drug treatments, and working across the retinal science community to create clinical trial endpoints that will strengthen and speed the all-important clinical trials process.
You can read the full report at: