An extreme close-up of the part of the retina responsible for our sharpest vision.
When someone loses their vision, their world goes dark for the rest of their lives. But recent developments hint that certain common causes of blindness might be reversible in the near future.
We are able to see because nerve cells at the back of the eye respond to light and transmit signals to the brain that we interpret as vision. Some rare genetic diseases and common non-genetic ones (including age-related macular degeneration and glaucoma) damage these cells, which then don't function as well and eventually die, causing blindness.
The body only has limited means to repair nerve cells and no way to replace dead ones, so damage to the nervous system that causes blindness is considered permanent.
Given that grim prognosis, the idea that we might able to restore sight to a significant subset of blind people just 15 years from now seems incredibly optimistic. But scientists at the National Eye Institute think they can make it happen.
"We don't think this is so far from reality here," Michael Steinmetz, the Director of Extramural Research for the National Eye Institute, told Business Insider.
To that end, the National Eye Institute recently announced the first round of projects to be funded through its Audacious Goals Initiative. The "audacious goal" that gives the initiative its name is to restore vision by regenerating lost nerve cells.
At this stage, as stem cell research in animal models and gene therapy clinical trials for people with genetic diseases have begun to show promise, the National Eye Institute is looking to find ways to get past barriers that have stalled progress on restoring blindness so far.
The first projects to be funded will help scientists measure the function of nerve cells involved with vision, going beyond current imaging techniques that just show what cells look like, Steinmetz said.
Researchers plan to map how nerve cells in the retina at the back of the eye interact and signal to each other. They'll also try to figure out exactly how large numbers of these individual cells respond to light without damaging living tissue.
Besides looking more closely at the cells in the retina, researchers will also work toward techniques that could image the optic nerve, a bundle of nerve cell fibers that carries visual information from the retina to the brain.
A final project aims to improve the resolution of current methods of imaging the retina, so researchers can focus on the activity of individual cells.
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Developing all of this imaging technology, while not work that's directly trying to regenerate nerve cells, would provide essential infrastructure for future projects. Before scientists can cure blindness, they need these imaging tools to get a better picture of what they're working with. Being able to look at individual cells and see how they're functioning will tell scientists what the interventions they test are actually doing at the cellular level.
These projects also have the potential to help physicians catch and treat vision-damaging diseases sooner, Steinmetz said. If physicians and their patients know something is going wrong in the eye early on, before damage shows up in the ways we are currently able to detect, they could likely implement therapies to preserve the nerve cells from further damage. Then, the disease could be stopped before it ever gets far enough to kill nerve cells or cause vision loss.
Time will tell whether or not we're able to regenerate nerve cells and cure blindness, and what role these imaging projects might play. But scientists at the National Eye Institute are optimistic that these are the first steps toward an audacious but achievable goal: making blindness treatable, not permanent.
"Even if we, in 10 or 15 years aren't able to completely restore normal vision," Steinmetz said, "we do hope that we are able to restore some kind of vision."