The human eye is one of the most complex visual organs amongst all life on Earth and for the first time ever, researchers have grown whole retinal tissue in a lab trying to understand how colour vision works.
A team of biologists from the Johns Hopkins University are working on treatments for eye diseases like colour blindness and macular degeneration, reports ScienceAlert. As part of their research they proceeded to also grow these organoids—tissue created in the lab. This was done to study human development at a cellular level.
"Everything we examine [in a retina organoid] looks like a normal developing eye, just growing in a dish," says Robert Johnston, biologist at Johns Hopkins. "You have a model system that you can manipulate without studying humans directly."
Johnston's team explore how a cell is chosen for its particular function in the mother's womb. What transforms a developing stem cell—in the womb—into cells with specific functions. For this research specifically, the team focused on vision and explored cell development, specifically ones that give people the ability to see blue, red, and green—the primary colours that make up all three cone photoreceptors in humans' eyes.
One of the reasons why this was necessary, explains the report is because most eyesight-based research is carried out on mice and fish, but they both do not have the dynamic colour vision that humans possess.
"Trichromatic colour vision differentiates us from most other mammals," says lead author Kiara Eldred. "Our research is really trying to figure out what pathways these cells take to give us that special colour vision."
Over months in the lab, cells grew to become fully-blown eye, retinal tissue. Researchers found that blue-detecting cells appeared first, then followed by red and green-detecting cells, notes the report.
"If we can answer what leads a cell to its terminal fate, we are closer to being able to restore color vision for people who have damaged photoreceptors," Eldred says. "This is a really beautiful question, both visually and intellectually—what is it that allows us to see color?"
The study was first published in the journal Science.