A contact lens that guides the growth of a young eyeball could stall worsening myopia in kids.
At the Optic Society’s annual meeting this week, a vision scientist called David Troilo will propose his idea to freeze the progression of childhood nearsightedness. His solution: A new kind of contact lens with varying powers, or focal lengths, mixed in.
Troilo, vice president and dean of academic affairs at the SUNY School of Optometry, studies growth of the human eye from early childhood to adulthood. His team fitted out marmosets with such “multizonal” lenses—with alternating rings of positive and negative focal lengths. They found that the eyeballs of the cuddly primates shrank. The team has also tested lenses with the variable focal lengths restricted to the outer edges.
A myopic eyeball is a too-long one, and as anyone who grew up with prescription glasses will tell you, it has trouble bringing distant objects into focus. Genes and reading habits are some of the factors that influence how near-sightedness gets worse in some children. But Troilo’s current work has another element at its focal point. That’s the hypothesis that the natural course of an eye’s growth can be swayed by the kinds of images it sees as it develops.
Regular corrective lenses for myopia have just a single focal length. They focus a sharp image onto just a section of a rather expansive retina. Because of the way the periphery of the retina responds to this image reception—goes this theory—the eyeball grows longer in response. And as the eyeball elongates, nearsightedness gets worse.
By messing with what the periphery of the retina sees, Troilio and team show that this trend can be stopped. Troilo writes in the summary to his talk that his graduated contact lens could stop myopia from getting out of hand, and shows promise to even reverse it altogether.