Pachymetry is a procedure used to measure the thickness of the cornea. An ultrasound device called the pachymeter is used to carry out this procedure. During refractive surgery procedures such as LASIK (laser-assisted in-situ keratomileusis), tissues from the cornea are usually removed. It is therefore necessary to ensure that enough tissue remains in the central part of the cornea to prevent ectasis, or abnormal bowing, of thin corneas. It is here that pachymetry plays a role. It has been discovered that extreme thinness of the cornea is closely related to the risk of glaucoma.

Optical pachymetry uses the principle called optical interferometry. Multiple peripheral measurements of the thickness of the cornea are obtained.

Pachymetry can be used to determine if the cornea is swollen. Conditions such as Fuch’s Dystrophy can cause the fluid in the cornea to accumulate thus causing an overall increase in the thickness of the cornea. Excessive use of contact lens is another factor that could cause swelling of the cornea. This may be difficult to see under the microscope. However, pachymetry will show a definite increase in thickness.

• Pachymetry assists greatly in the diagnosis of glaucoma.
• Pachymetry helps determine the thickness of the cornea in potential refractive surgery candidates
• Pachymetry helps in monitoring the effects of various therapies that make use of lasers, filtering surgery or eye drops.