by Sean McGarry
Retrieved from SciLifeLab
A seemingly inevitable condition for many, vision loss is present in nearly 12 million Americans, typically common in people ages 18 and up. However, there are recent scientific developments that hold promise in restricting the severity of these impairments, possibly preventing extreme repercussions associated with them such as blindness. With the utilization of stem cells and optometric therapies, scientists are actively attempting to combat vision disorders, namely Stargardt’s Macular Dystrophy and Retinitis pigmentosa, in a way never done before.
Stargardt’s Macular Dystrophy (STGD), affecting over eight million Americans, is a mutation in the ABCA4 gene which causes proteins that excrete toxic-byproducts to malfunction, damaging photoreceptor cells. Thus, an individual’s vision blurs and becomes progressively worse as more active photoreceptor cells are impaired. STGD is an autosomal recessive disorder, meaning that if two parents each have a faulty copy of the ABCA4 gene, their offspring is almost always 25% likely to inherit the condition. To maintain a person’s vision indefinitely, scientists have implemented stem cells into the macula of said people’s eyes in order to replace the degenerate retinal cells, recycling photopigments and thus restoring Vitamin A. A study published in 2015 by Professor Steven D. Schwartz (et al.) found that, after a span of three years, a great percentage of individuals (72%) saw an increase in subretinal pigmentation, thus proving the efficacy of the treatment.
Another notable vision disorder is Retinitis pigmentosa, a direct result of cells in the eye that retrieve light failing to function. Optogenetic therapies have been used to correspond wavelengths of light to nerve cell activity in the brain. Earlier versions of the operation used signals from a protein in algae, which proved ineffective due to the great amount of light needed for it to work. “It’s like staring at the sun in the desert,” remarks José-Alain Sahel, a specialist in the optometry field. Amber light, on the other hand, would be much more effective and less harmful on the patient. Scientists in this study inserted an adeno-associated virus into ganglion cells in order for them to transmit signals to visual remotes in the brain. Optometrists have created goggles that regulate the pulse at which amber light interacts with a person’s eyes, enhancing vision. While the viability of these goggles is currently limited, there is hope that alternative approaches to stem cell therapy can soon be employed. “For now, all we can say is that there is one patient…with a functional difference,” says neuroscientist Botond Roska in his closing statement.
The concept of treating vision loss is one that is highly variable, and scientists are continuously working to devise ways in which eyesight can be best restored. Nonetheless, it will be interesting to see what the future holds for optometry and the extent to which conditions like Stargardt’s Macular Dystrophy and Retinitis pigmentosa can be addressed.
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