Central Corneal Thickness (CCT or Pachymetry)

Measuring the Central Corneal Thickness (CCT) or Pachymetry, has become a standard ancillary test in the complete eye examination for patients at risk of having glaucoma. The first widespread use of this test was as a late addition to the Ocular Hypertension Treatment Study (OHTS) after it had been observed that patients with thicker corneas were less likely to develop glaucoma than people with thinner corneas.

There is a tendency though to misinterpret the findings of pachymetry as being a correction factor when measuring intraocular pressure. Pachymetry is an independent risk factor for progression of glaucoma, not a correction factor for IOP. This is discussed in greater deal on this episode of my Talking About Glaucoma podcast series. Patients with thinner corneas are at greater risk to have their glaucoma get worse at lower eye pressure readings and those with particularly thick corneas can be viewed as having a level of protection against developing glaucoma damage.


(c) 2009 Robert M. Schertzer, MD, MEd, FRCSC; reviewed for relevance 2020, 2021

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This post was written by Rob Schertzer