Millions of Americans live with vision problems ranging from mild blurriness to severe vision loss. Glasses and contact lenses can correct many common problems, but some people turn to surgery for a more permanent solution. Hundreds of thousands of Americans undergo corrective eye procedures each year, including LASIK, which uses a laser to reshape the cornea and improve how the eye focuses light.
Now researchers are investigating a very different approach. Instead of cutting away corneal tissue with a laser, they are testing a technique that temporarily makes the cornea flexible enough to be reshaped. Early experiments using rabbit eye tissue suggest the method could potentially correct vision in about a minute, without incisions and with much simpler equipment than LASIK requires.
The cornea is the clear, dome-shaped surface covering the front of the eye. It plays a major role in vision by bending incoming light so it can be focused onto the retina, the light-sensitive tissue at the back of the eye. The retina then converts that light into signals that the brain interprets as images.
When the cornea does not have the right curvature, light may not focus properly. This can cause refractive errors such as myopia, better known as nearsightedness, in which distant objects appear blurry. LASIK corrects these problems by using specialized lasers to remove extremely precise amounts of corneal tissue and change its shape.
The procedure is widely used and generally considered safe, but it still involves permanently removing tissue and can carry side effects and other risks. Michael Hill, a professor of chemistry at Occidental College, puts it more bluntly: "LASIK is just a fancy way of doing traditional surgery. It's still carving tissue -- it's just carving with a laser." That led researchers to consider a very different question: Could the cornea be reshaped without cutting it at all?
Hill and collaborator Brian Wong are studying a technique called electromechanical reshaping (EMR). Rather than physically removing tissue, EMR uses a small electric potential to temporarily alter the chemical environment inside the tissue. "The whole effect was discovered by accident," explains Wong, a professor and surgeon at the University of California, Irvine.
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