corneal topography

Corneal topography, also known as photokeratoscopy or videokeratography, is a non-invasive medical imaging technique for mapping the surface curvature of the cornea, the outer structure of the eye. Since the cornea is normally responsible for some 70% of the eye's refractive power, its topography is of critical importance in determining the quality of vision.
The three-dimensional map is therefore a valuable aid to the examining ophthalmologist or optometrist and can assist in the diagnosis and treatment of a number of conditions; in planning refractive surgery such as LASIK and evaluation of its results; or in assessing the fit of contact lenses


Corneal pachymetry is the process of measuring the thickness of the cornea using contact methods, such as ultrasound and confocal microscopy (CONFOSCAN), or noncontact methods such as optical biometry. Corneal Pachymetry is particularly essential prior to a LASIK procedure for ensuring sufficient corneal thickness to prevent abnormal bulging out of the cornea, a side effect known as ectasia. The instrument used for this purpose is known as a pachymeter.

Corneal Pachymetry is essential for other corneal surgeries. By using the corneal pachymetry the surgeon will reduce the chances of perforation of the eye and improves his surgical outcome. Corneal pachymetry is also considered an important test in the early detection of glaucoma.