Laser Technologies—Excimer Laser

The excimer laser is a unique type of laser that neither burns nor cuts tissue. Each pulse of excimer laser removes 0.25 microns of tissue (human hair is about 70 microns thick).

 

This refers to laser vision correction that corrects the myopia/hyperopia and astigmatism of the patient based purely on his or her refractive error. No additional enhancements are used to shape the cornea to reduce surface irregularities and aberrations.

 

In order to treat near-sightedness (myopia), the laser makes the central cornea less curved. More flattening is needed for a greater degree of myopia. This leads to a greater change in cornea curvature at the edge of the treatment zone, which can then lead to night vision problems and reduced quality of vision due to spherical aberration.

 

Aspheric treatment refers to the use of advanced computer generated laser pulses that help to smoothen the change in cornea curvature at the edge of the treatment zone, thereby reducing night vision problems through reducing spherical aberration. This treatment modality is a great help for those with high myopia.

 

Myopia, hyperopia and astigmatism are referred to as "lower order" aberrations. In addition to these, some of us have complex "higher order' aberrations (surface or internal irregularities) that are not correctable with glasses or contact lenses but can also decrease our quality of vision.

 

A wavefront is obtained by casting light into the eye and measuring the pattern of the reflected light. Wavefront-guided treatment refers to correction of the myopia / hyperopia and astigmatism, as well as, the higher order aberrations of the eye using the wavefront pattern obtained. This is suitable for those with a high amount of wavefront aberrations.

 

In this treatment modality, the laser is aided by a special software to reduce the amount of cornea tissue removed for the same degree of refractive correction. This is useful for those with borderline cornea thickness for full correction using standard LASIK.

 

This refers to a laser software that smoothens the surface irregularities of the eye based on a map of the cornea surface, in addition to correcting myopia/ hyperopia and astigmatism. The map is akin to the geographical maps travellers use for navigating over land. The treatment smoothens out the lumps and bumps of the cornea resulting in a more ideal finished surface. This treatment can offer a high quality of post-operative vision, especially in people with significant surface irregularities.​