BACKGROUND: An opthalmologist and his team at the University of California in Irvine have invented a new laser surgery technique to perform cornea-transplant surgery. This new surgery can replace traditional handheld surgical blades and improve recovery time and vision for patients. The Irvine team performed simulated transplant surgery on 14 donated human corneas and compared their results to traditional transplant results. Clinical trials began this summer at UC-Irvine.
HOW IT WORKS: Cornea transplants have traditionally only been performed in severe cases, since the majority of transplant recipients don't see improvements in their vision for at least six months, and even then strong glasses or contact lenses are needed because of remaining distortions. The cornea is slow to heal, and the transplant can remain vulnerable to injury for the rest of the patient's life. The new technique allows for special inter-locking cuts -- akin to dowels in wood -- that enable the edges to interlock. The treated area heals much faster -- within three months -- and may be as much as 10 times stronger compared with conventional transplants. The vastly improved precision also means that the laser can create complex shapes impossible to achieve with conventional surgery. The cuts are made not with the round blade used for the past 50 years, but by the same kind of laser used in LASIK vision correction surgery. This laser fires 15,000 pulses of light over a single second.
LASING A PATH: Laser eye surgery uses a pulsed, tightly focused beam of light to vaporize a tiny portion of the cornea. By controlling the size, position and number of laser pulses, the surgeon can precisely control how much of the cornea is removed. Reshaping the cornea changes the focal point of the eye, resulting in corrected vision. In the Irvine technique, the laser pulses are so brief, that in one quadrillionth of a second, a pulse of laser light could travel only the width of three human hairs. This is incredibly precise and controlled: on its own, in one second light can travel around the equator of the Earth seven times. The pulses are controlled by sophisticated optics and a computer to ensure they target the correct sections of the cornea -- similar to how the perforations in paper sheets allow the paper to be torn cleanly.