Corneal pachymetry measures the thickness of the cornea.
Alternative Names:
Corneal Thickness

What to Expect

  • Topical anesthetic (numbing) eye drops are administered.  
  • An ultrasonic probe is held against the cornea and several readings are taken.  
  • Patients will be asked to look straight ahead and not blink during data acquisition.
  • The test will take approximately one minute per eye.

How the Test Feels

Patients may experience burning and/or stinging from the topical anesthetic.

Why the Test is Performed

Corneal pachymetry can aid in the diagnosis of corneal thinning and is helpful to assess the function of the corneal endothelium (posterior layer of the cornea).  This test is useful in assessing a patient’s eligibility for refractive surgery.  Recently, corneal thickness has also been found to be useful in interpreting intraocular pressure.


  • Normal Values
    Normal corneal thickness ranges from about 500 to 575 microns.


  • Abnormal Results
    Abnormally thick or thin measurements may indicate
    • Corneal thinning
    • Corneal edema (swelling)
    • Lower or higher than suspected intraocular pressure