Using a type of human stem cell, researchers have now created a three-dimensional (3D) functional human retinal tissue in the laboratory for the first time.
"We have basically created a miniature human retina in a dish that not only has the architectural organisation of the retina but also has the ability to sense light," claimed M. Valeria Canto-Soler, an assistant professor at John Hopkins University's school of medicine.
The retinal tissue created in the laboratory - using human induced pluripotent stem cells (iPS) - includes functioning photoreceptor cells capable of responding to light, the first step in the process of converting it into visual images.
"The work advances opportunities for vision-saving research and may ultimately lead to technologies that restore vision in people with retinal diseases," she noted.
Using a simple, straightforward technique they developed to foster the growth of the retinal progenitors, the researchers saw retinal cells and then tissues growing in petri dishes.
The growth corresponded in timing and duration to retinal development in a human foetus in the womb.
Moreover, the photoreceptors were mature enough to develop outer segments - a structure essential for photoreceptors to function.
However, Canto-Soler cautioned that photoreceptors are only part of the story in the complex eye-brain process of vision, and her lab has not yet recreated all of the functions of the human eye and its links to the visual cortex of the brain.
The achievement could eventually enable genetically engineered retinal cell transplants that halt or even reverse a patient's march toward blindness.
The findings appeared in the journal Nature Communications.
