Laser vision correction | Industrial, Medical And Specialty Gases | Coregas Australia

Laser vision correction

Laser vision correction surgery is often carried out to treat myopia and other sight disorders. The excimer lasers require specialty gases mixtures for their operation.

Laser vision correction as a type of ocular surgery is now common for permanent correction of sight disorders such as myopia, astigmatism and hyperopia. There are perhaps more than one million operations of this type conducted each year worldwide.

To conduct the surgery a 193 nm UV laser is used; generation of this laser beam requires the gases argon and fluorine to be present. In the laser the argon reacts with the fluorine, producing argon monofluoride, which is a temporary complex. The result is an exciplex laser (often also referred to as an excimer laser) that radiates far ultraviolet light energy at a wavelength of 193 nm.

UV light from this argon fluoride (ArF) laser is absorbed by biological matter such as human eye tissue. The ArF laser dissociates the molecular bonds of the surface tissue, which disintegrates gently through ablation rather than burning. The ArF laser is therefore ideal for surgery because it can remove very fine layers of surface material with almost no heating or change to the substrate. These properties make ArF lasers well suited to especially delicate eye surgery.

Typical gas mixture compositions

Many of the leading vision correction laser manufacturers have their own proprietary specifications for the gas mixture required for their equipment. The typical range would be between 0.1% and 1.0% fluorine, 1 to 25% argon in a balance of helium. Alternatively, a neon balance is sometimes specified with a typical mixture of the composition 1% fluorine, 3.5% argon in a balance of neon.