What is pachymetry?

Pachymetry, or corneal pachymetry,  is a common test for glaucoma and usually part of the comprehensive eye exam. It measures the thickness of the cornea, which sets a baseline for other glaucoma tests and helps determine eye health. The test may use ultrasound techniques, which require physical contact with the cornea, so numbing drops are used on the eye first. The doctor uses an ultrasonic wave instrument to measure the cornea's thickness. In traditional optical pachymetry, thickness of the cornea is determined with a special microscopic viewer, and no physical contact is made with the eye and numbing drops are unnecessary. It is not as easy, quick, or as accurate as the ultrasound test, however.
Currently, the word pachymetry is synonymous with measuring the thickness of the cornea. This is important in the evaluation of a cornea for LASIK and, incidentally, glaucoma. The process of pachymetry is painless and easy. It is performed by instruments that use one of two different methods. One instrument uses ultrasound techniques, and the other uses confocal microscopy techniques. Older methods included those that were non-contact (with the cornea) and used strictly optical methods.

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