It’s not just an ambitious goal, it’s an audacious one. That’s how the National Eye Institute (NEI) describes its coordinated effort to find ways to restore sight in eyes that have been damaged by blinding diseases, including AMD and glaucoma.
NEI has pledged research funds to support this initiative over a five-year period, with the first grants announced at the 2015 annual meeting of the Association of Research in Vision and Ophthalmology (ARVO). Initially, research will focus on the retina, where light-sensing photoreceptors and retinol ganglion cells (RGCs) receive and record visual signals. Scientists are looking for ways to protect these cells and keep them alive under stress of disease.
The optic nerve, a bundle of more than one million nerve fibers, or axons, serves as the superhighway for transmitting this visual information from the eye to the brain. And while anti-glaucoma medications can be effective in addressing pressure in the eye, there is currently no medication for the damage that glaucoma causes to the optic nerve. Unlike most tissues in the body, photoreceptors, RGCs and optic nerve fibers (known as “axons”) are not able to regenerate naturally once they become damaged. Vision loss is permanent. That is why BrightFocus recently funded a major study by Jeffrey Goldberg, MD, PhD, of Stanford University, to clinically test the role of an particularly promising growth factor in protecting the optic nerve from damage by glaucoma.
For the same reason, NIH also is funding research into ways to regrow or replace these tissues, and Dr. Goldberg is also a part of that effort. At ARVO, he took part in an NEI-sponsored panel on the Audacious Goals initiative. Last year he was awarded a $1 million shared grant from the U.S. Department of Defense (DoD) for a two-year project to develop whole-eye transplantation techniques in an animal model. That grant hinged off Goldberg’s earlier BrightFocus-funded research projects, including a 2010-12 grant, completed while he was at University of Miami, to investigate cell therapy techniques to enhance optic nerve regeneration in a model that mimics glaucoma. More recently, Goldberg collaborated on a 2013-15 BrightFocus grant to Kenneth J. Muller, PhD, at University of Miami, who’s investigating ways to transplant RGCs into retinas in a mouse model of glaucoma.
In an interview last year, Goldberg described their efforts and said, “the biggest scientific hurdle is not hooking up all the eye’s tiny blood vessels, or its musculature,” but rewiring the neural connections between the eyes and the brain. Beyond that, the brain needs to be retrained (some say reprogrammed) in order for visual signals from restored photoreceptors and RGCS to be translated into recognizable images.
The dynamic process we call “sight” normally begins at the earliest developmental stages in humans and continues over a lifetime. In people who have lost or never had sight, the neural connections that make it possible to interpret images from patterns of light have to be made new or reestablished. As a result, some of strongest backers of this research, who are most optimistic about its eventual success, find it necessary to caution that “success” in restoring vision, in these earliest experiments, will be a crude approximation of normal vision.
Yet, for the 285 million people around the world who are blind or vision-impaired, it’s a welcome prospect and one that offers new hope. As an NEI video states, “The goal is audacious, but the impact would be amazing.”