Early test of new laser-free eye treatment shows promise

Scientists have developed a potential new method for corrective eye surgery that doesn't use lasers, but instead shapes the eye's outer surface using an electrical current.

The method has so far been tested only in animals, but the researchers who pioneered it hope that it will someday offer an alternative or complement to conventional LASIK surgery. The team presented their findings Aug. 18 at the American Chemical Society's annual meeting in Washington, D.C.

LASIK is the most popular type of "refractive" laser surgery, which adjusts how light passes through the clear outer layer of the eye, or cornea. It can correct the changes in the cornea that cause nearsightedness, farsightedness and astigmatism. For those looking to ditch glasses or contact lenses, LASIK has become a common solution: since its approval in 1999 this surgery has treated more than 10 million people in the U.S.

The cornea bends light to focus it on the retina, the light-sensitive tissue at the back of the eye, before the visual information is sent to the brain to be processed. Irregularly shaped corneas don't focus light properly, resulting in impaired vision. While LASIK can correct this irregularity, it can have some potential side effects like eye pain and irritation. More rarely, incisions on the eyes made by lasers can compromise the organ's structural integrity.

To find another possible method to reshape the cornea without lasers or incisions, Michael Hill, a chemist at Occidental College in Los Angeles, and Dr. Brian Wong, a surgeon at UC Irvine School of Medicine, began experimenting with a process called electromechanical reshaping (EMR) to mold tissues in the body. This technique previously enabled the researchers to reshape rabbit ears and alter scars on pigs' skin, approaches that they plan to develop for eventual use in human patients.

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EMR uses electricity to alter tissues. Many collagen-containing tissues in the body, including the cornea, are held in place by oppositely charged components attracted to each other like magnets. These tissues also contain water, so zapping the tissues with electricity ultimately lowers their pH, making them more acidic. With the pH altered, the attraction between opposite charged components is unlocked, loosening up the tissue and making it moldable. When scientists then cut the electricity and restore the tissue's original pH, it locks back into the new shape.

Hill and Wong wondered whether EMR could be used to reshape the cornea. To see, they ran tests with rabbit eyes in lab dishes. They created a platinum contact lens template to imitate the corrected shape of a cornea, placed it over a rabbit eyeball in saline solution, and sent an electric current through the platinum lens. Within about a minute, the rabbit eyeball's cornea molded around the contact lens; the whole process took about the same time as LASIK surgery.

The researchers tested this method on 12 rabbit eyeballs, 10 of which were treated as if they had myopia, or nearsightedness. The treatment successfully reshaped the cornea in a way that would better focus light on the retina, and the cells in the eyeballs were not damaged in the process.

The method might also be able to reverse cloudiness in the cornea, Hill and Wong told Live Science, which is currently only treatable through a corneal transplant. That's something they're still experimenting with, but in theory, tweaking the pH of the cornea could also help counter the cloudiness, they think.

Although Hill and Wong are hopeful about the promise of EMR eye treatments, this procedure is in very early stages, they said. The next steps are studies in living animals, and more specific tests to assess which specific vision issues this process can correct, like near- and farsightedness and astigmatism.

"Like any other medical technology it's a process, and you have to go through a fair amount of testing," Wong told Live Science. This includes testing more with animal tissues and with live animals, resolving any issues that arise, and eventually moving on to various phases of clinical trials in humans.

These early preclinical tests of the method are promising in that they show the procedure is safe for eye cells and that the cornea remains clear after EMR alteration, Maria Walker, an optometrist at the University of Houston, told Live Science. But further testing would need to investigate possible longer-term effects. "It might be safe and the cornea might be clear, but then what happens in a month?" said Walker.

Some issues with laser eye surgery, although rare, come from heat transfer to the cornea, which EMR techniques would avoid, Walker noted. "My impression is cautiously optimistic," she said. "I think it's promising."

If the method is proven to be successful and safe in humans, it could someday offer an alternative or complement to LASIK that's possibly reversible — since it's not actually removing any tissue, just rearranging it — and cheaper, the researchers suggest.

"You can't treat every single problem of the cornea with LASIK, there are areas where it simply doesn't have application," said Wong. There are certain patients who aren't good candidates for LASIK. "So I think there are areas where this would have value complementing LASIK."

The cost of EMR equipment would also be cheaper than laser equipment, said Wong, which could potentially make it accessible to more patients looking to correct their vision.