A New Way to Fix Cataracts?

This article is based on a Science Friday interview and was originally published on PRI.org.

As people age, their vision becomes less crisp.

Small print gets harder to read. Often the culprit for worsening vision is cataracts: a clouding of the lens in the eye. There are currently effective treatments for cataracts: Usually the lens is surgically removed. Now, however, researchers think they might be able to use stem cells to grow new lenses for people who suffer from cataracts.

Two studies in the journal Nature looked at new research into using stem cells for eye therapy. One team, a group headed by Khang Zhang of the University of California, San Diego, and Yizhi Liu of Sun Yat-sen University in Guangzhou, China, removed a cataract from test subjects and used the subject’s own stem cells to regenerate a lens. The procedure was tested in animal models and also in 12 human infants.

Cell biologist James Funderburgh, an eye expert who was not affiliated with these studies, explains:

“They had the idea that the cells on the outside of the lens…might actually be stem cells. So they did some rather elegant experiments where they showed that they did have the properties of stem cells,” Funderburgh says. “They grew them in a dish, and actually, they turned into little lenses that would focus the light. So they had this hypothesis that maybe in some cases you don’t need to put a plastic lens into the eye—that, actually, those stem cells could help actually regenerate a new lens.”

Another team, led by Kohji Nishida at Osaka University Graduate School of Medicine in Japan, used human stem cells to grow differentiated eye tissue types in a petri dish. The corneal tissues were able to restore sight in rabbits.

“They went in and did a normal cataract operation except, rather than replacing [the rabbit’s lens with] a plastic lens they just left the lenses—a little flat disk—in the eye, and within a few months they showed that these lenses…had grown and turned into new fiber cells and regenerated the lens—a perfectly transparent lens,” Funderburgh says,

The new technique has since been tried on infants with vision problem in clinical trials with much success.

“They did 12 babies under two, 24 eyes,” Funderburgh says. “They removed the material from the lens as if they were doing a normal cataract operation and just left it that way. And within six to eight months, all of these lenses had regenerated. They had good vision and no complications.”

Funderburgh thinks the procedure could start being used in the United States by surgeons almost immediately.

“A surgeon could just go ahead and do this operation,” Funderburgh says. “Slightly different technique—they approach the lens from the side rather than the front but other than that…it should be usable almost immediately…You might need an institutional review board to make sure that surgical procedure is okay, but I don’t think the FDA would need to be involved.”