Excimer laser eye surgery

Briefly, laser stands for “light amplification by stimulated emission of radiation”. Laser light is created when energy is applied to a mixture of gases. Two gaseous elements such as argon and fluoride in a helium premix are jolted to a higher energy state with thousands of volts of electricity. These elements combine to form an unstable compound. As the excited ionized atoms dance within a mirrored tube that reflects the light back at them, they release an intense concentration of light energy. Eventually, the light beam becomes so energized that part of it escapes from the tube through a hole in the semi-silvered mirror. Such laser light – unlike sunlight – is focused in one direction at one wavelength. In other words, the light rays vibrate together in phase to form a “coherent” monochromatic laser beam.

The cool excimer laser, the most technologically advanced surgical tool to treat refractive errors, has revolutionized vision correction surgery. This remarkably precise ultraviolet laser creates invisible pulses of light that remove microscopic amounts of corneal tissue. Controlled by customized software, a computer calculates the number of laser shots required to achieve a patient's targeted refraction.