Total visual loss affects 36 million individuals worldwide1. They are unable to discern forms or even light sources. The majority of these individuals are blind due to treatable conditions such as cataracts; they just lack access to proper medical treatment. The other millions, on the other hand, are blind as a consequence of diseases for which there is now no viable therapy.
Degeneration of the retina is the main cause of blindness in high-income nations where avoidable causes of visual impairment are regularly treated. This tissue, which is located at the back of the eye and includes specialised cells that respond to light and interpret visual information, is critical to vision. Photoreceptor cells, also known as rods and cones, turn light into electrochemical impulses when it hits the retina. Before reaching retinal ganglion cells, these impulses pass via a complicated network of other neurons, including bipolar cells, amacrine cells, and horizontal cells. The optic nerve is formed by the long extensions, or axons, of those cells, which carry signals from the retina to the brain’s visual cortex, where they are processed as pictures.
The loss of photoreceptor cells, which reduces the eye’s sensitivity to light, is a frequent symptom of retinal diseases. This loss is caused by the failure of epithelial cells that form a layer at the rear of the retina called the retinal pigment epithelium in certain retinal diseases, such as age-related macular degeneration (AMD) (RPE). The RPE maintains the integrity of photoreceptor cells by cleaning up harmful by-products generated during light reactions and supplying nutrients. The primary cause of blindness in retinal diseases with healthy photoreceptors is degeneration of retinal ganglion cells.
The variety of causes of vision impairment makes finding remedies more challenging. However, advancements in many areas are increasing optimism that nearly all types of retinal disorders may be treated in the near future.
One option is to use functional prosthesis to supplement or replace injured eyes. At the moment, bionic eyes can only restore limited vision, but researchers are working to improve the devices’ capabilities. Gene therapy is another possibility. Researchers are trying to expand this technique to additional individuals and situations. It is now accessible to those with certain genetic mutations. Some researchers are also working on therapies based on optogenetics, a similar method that involves genetically modifying cells to restore light sensitivity in the retina. This study is still in its early stages, but researchers believe that since it is agnostic to the causes of retinal degeneration, it will eventually be able to assist a broad variety of individuals. In addition, attempts to restore lost or damaged retinal cells in situ or via cell transplants suggest that even late-stage retinal diseases may be treated in the future.
Much of this research is still in its early stages. Hauswirth, on the other hand, is optimistic about the progress that has already been achieved. He recalls having to inform people that he couldn’t help them 10 years ago. “That has completely altered for many of these diseases.”