"The whole effect was discovered by accident," Wong explains. "I was looking at living tissues as moldable materials and discovered this whole process of chemical modification."

The method exploits the chemistry that gives tissues their shape. The cornea is rich in collagen, a structural protein also found in skin, cartilage and tendons. Inside collagen-rich tissue, electrically charged components attract one another and hold the structure rigid.

Because these tissues also hold a lot of water, applying an electric potential shifts their pH — the scale that measures how acidic or basic a substance is. Lowering the pH makes the tissue more acidic and temporarily weakens the electrical attractions that keep it stiff. During that brief window, the tissue becomes moldable. Once normal pH returns, the interactions snap back and the tissue holds its new form.

Researchers had previously used EMR to reshape cartilage-rich rabbit ears and to modify scars and skin in pigs. The cornea was an appealing next target because its exact curvature determines how well the eye focuses.

A platinum "contact lens" as a mold

For the new experiments, the team built platinum "contact lenses" shaped as molds for the desired corneal form. They placed the lenses over rabbit eyeballs immersed in saline solution meant to mimic natural tears. Because platinum conducts electricity, the lens doubled as an electrode. When the researchers applied a small electric potential, it produced a carefully controlled pH change inside the cornea.

Within about a minute, the cornea's curvature shifted to match the lens. That is roughly comparable to the laser portion of a LASIK procedure, but the EMR method required no incision and could potentially run on simpler, cheaper equipment.

The researchers tested the approach on 12 rabbit eyeballs, treating 10 as if they had myopia. In every one of those eyes, EMR changed the cornea enough to reach the intended focusing power — an optical change that would be expected to improve vision if it could be reproduced safely in a living eye. The cells in the treated eyes survived, thanks to careful control of the pH gradient so the chemical changes stayed large enough to reshape the cornea without excessive damage.

The experiments also hinted at a second use. In separate tests, EMR appeared able to reverse some chemically induced corneal cloudiness — a condition currently treatable only through a full corneal transplant. If that result holds up in future studies, the technique could extend beyond ordinary vision correction.

A long road ahead

The researchers are candid about the limits. So far, the vision-correction work has used isolated rabbit eyeballs, not living animals. The next step, in Wong's words, is "the long march through animal studies that are detailed and precise," beginning with tests in a living rabbit. Researchers still need to determine which refractive errors EMR could correct — possibly nearsightedness, farsightedness and astigmatism, a common condition caused by an irregularly shaped cornea or lens. They also don't yet know how stable the reshaping is over time, or whether repeated or long-term effects appear in living eyes.

Progress has also slowed by uncertainty around the team's scientific funding.

"There's a long road between what we've done and the clinic. But, if we get there, this technique is widely applicable, vastly cheaper and potentially even reversible," Hill concludes.

The research was funded by the National Eye Institute of the National Institutes of Health and the John Stauffer Charitable Trust.