Safer, cheaper vision correction

 Vision correction without lasers or surgery, An alternative to LASIK 

Millions of Americans have altered vision, ranging from blurriness to blindness. But not everyone wants to wear prescription glasses or contact lenses. Accordingly, hundreds of thousands of people undergo corrective eye surgery each year, including LASIK, a laser-assisted surgery which reshapes the cornea and corrects vision. The procedure can result in negative side effects, prompting researchers to take the laser out of LASIK by remodeling the cornea, rather than cutting it, in initial animal tissue tests. Researchers are developing a futuristic alternative to LASIK which reshapes the eye without lasers or incisions. Using mild electrical pulses and platinum contact lenses, they temporarily soften the cornea so it can be molded into a new shape. Early tests on rabbit eyes successfully corrected nearsightedness in about a minute while preserving the eye’s structure.

Hundreds of thousands of people undergo corrective laser-based eye surgeries each year, but researchers are hoping to change that thanks to a corneal reshaping technique currently in development. Human corneas are dome-shaped, clear structures that sit at the front of the eye, bending light from surroundings and focusing it onto the retina, where it’s sent to the brain and interpreted as an image. But if the cornea is misshapen, it doesn’t focus light properly, resulting in a blurry image. With LASIK, specialized lasers reshape the cornea by removing precise sections of the tissue. This common procedure is considered safe, but it has some limitations and risks, and cutting the cornea compromises the structural integrity of the eye. Millions around the world live with blurry vision, nearsightedness or more severe sight problems. While glasses and contact lenses help many people, millions have turned to corrective procedures such as LASIK to sharpen their eyesight. But scientists are now exploring a very different approach which could someday reshape the eye without lasers, cutting or invasive surgery.

Researchers from Occidental College and the University of California, Irvine have been developing an experimental technique called electromechanical reshaping (EMR). Instead of carving away tissue like LASIK, the method temporarily softens the cornea so it can be gently molded into a new shape. Early tests in rabbit eyes suggest the technology may one day provide a cheaper, less invasive alternative to traditional laser eye surgery. The idea behind EMR emerged unexpectedly during earlier experiments involving cartilage and other collagen-rich tissues. "The whole effect was discovered by accident," explains Brian Wong, a professor and surgeon at the University of California, Irvine. "I was looking at living tissues as moldable materials and discovered this whole process of chemical modification." Collagen-rich tissues throughout the body, including the cornea, maintain their shape through networks of charged molecules which hold the structure together. Because these tissues contain large amounts of water, scientists found that applying a mild electric current can temporarily alter the tissue's acidity level, or pH. As the pH shifts, the molecular bonds holding the tissue rigid begin to loosen. This briefly makes the tissue flexible enough to reshape. Once the pH returns to normal, the tissue stiffens again and locks into its new form. Researchers had previously tested EMR on rabbit ear cartilage, pig skin and scar tissue. The cornea became one of the most promising targets because even small changes in its curvature can dramatically improve vision.

In the body, the shapes of many collagen-containing tissues, including corneas, are held in place by attractions of oppositely charged components. These tissues contain a lot of water, so applying an electric potential to them lowers the tissue’s pH, making it more acidic. The cornea is the clear, dome-shaped surface at the front of the eye. It bends incoming light and helps focus images onto the retina. When the cornea is too steep, too flat or unevenly shaped, vision becomes blurry. LASIK corrects those problems by using lasers to remove tiny amounts of corneal tissue and permanently reshape the eye. Although the procedure is widely used and generally considered safe, it can sometimes lead to complications including dry eyes, glare, halos and weakened corneal structure. Michael Hill, a chemistry professor at Occidental College, says the basic concept behind LASIK still comes down to tissue removal. "LASIK is just a fancy way of doing traditional surgery. It's still carving tissue -- it's just carving with a laser." This limitation inspired researchers to search for a way to reshape the cornea without making incisions at all.

In this work, the team constructed specialized, platinum “contact lenses” which provided a template for the corrected shape of the cornea, then placed each over a rabbit eyeball in a saline solution meant to mimic natural tears. The platinum lens acted as an electrode to generate a precise pH change when the researchers applied a small electric potential to the lens. After about a minute, the cornea’s curvature conformed to the shape of the lens, about the same amount of time LASIK takes, but with fewer steps, less expensive equipment and no incisions. The team tested the procedure on 12 rabbit eyeballs. Ten were treated to simulate correction for myopia, also known as nearsightedness. In those eyes, the corneas successfully achieved the intended focusing power which would correspond to improved vision. Importantly, the cells within the tissue remained alive because the researchers carefully controlled the pH changes during treatment.

The researchers also reported another intriguing possibility. In separate experiments, the same technique appeared capable of reversing some forms of chemical cloudiness in the cornea. Today, severe corneal clouding often requires a full corneal transplant. Scientists say EMR could potentially avoid some of the major drawbacks associated with LASIK and related procedures such as PRK. Because the method does not remove corneal tissue, it may preserve more of the eye's natural structural strength. The electromechanical reshaping technique successfully flattened rabbit cornea from its original shape to a corrected one. In all the “myopic” eyeballs, the treatment dialed in the targeted focusing power of the eye, which would correspond to improved vision. The cells in the eyeball survived the treatment, because the researchers carefully controlled the pH gradient. Additionally, in other experiments, the team demonstrated that their technique might be able to reverse some chemical-caused cloudiness to the cornea, a condition that is currently only treatable through a complete corneal transplant. Laboratory imaging studies using optical coherence tomography (OCT), confocal microscopy and second-harmonic generation microscopy also suggested that the cornea's collagen structure remained largely intact after treatment. Researchers reported no major loss of transparency or obvious tissue damage in the early experiments.

More recent reports and engineering updates have continued to refine the technology. Scientists are now developing advanced electrode contact lenses capable of monitoring corneal shape, hydration and transparency during treatment. Researchers have also explored whether EMR could eventually be adapted for conditions beyond nearsightedness, including farsightedness, astigmatism and certain reconstructive procedures involving cartilage-rich tissues. Some scientists believe the approach could ultimately become far less expensive than laser-based surgery because it may not require large, complex laser systems. Despite the excitement surrounding the technology, researchers caution that EMR remains highly experimental. This research was funded by the National Eye Institute of the National Institutes of Health and the John Stauffer Charitable Trust. Though this initial work is promising, the researchers emphasize that it is in its very early stages. Next up is the long march through animal studies that are detailed and precise including tests on a living rabbit rather than just its eyeball. They also plan to determine the types of vision correction possible with EMR, such as near- and far-sightedness and astigmatism. Though the next steps are planned, uncertainties in the team’s scientific funding have put them on hold. 

"There's a long road between what we've done and the clinic," concludes Hill. "But, if we get there, this technique is widely applicable, vastly cheaper and potentially even reversible." Researchers are also continuing to study how precisely the procedure can correct different types of vision problems and whether long-term side effects might emerge after treatment. For now, LASIK remains the standard option for surgical vision correction. But EMR has opened the door to a future where fixing blurry vision may no longer require lasers, cutting, or permanent tissue removal. The American Chemical Society (ACS) is a nonprofit organization founded in 1876. ACS is committed to improving all lives through the transforming power of chemistry. Its mission is to advance scientific knowledge, empower a global community and champion scientific integrity, and its vision is a world built on science. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge.