Article Date: 3/1/2004

coding q & a
Corneal Pachymetry
Learn about other uses for this measurement and how to code for it.
By Suzanne Corcoran, C.O.E.

Q What is corneal pachymetry?

Corneal pachymetry is a measurement of the thickness of the cornea. In general, the normal human cornea measures approximately 550 µm thick centrally and a full millimeter thick peripherally. Eyecare practitioners most often use a pachymeter to measure the central cornea, although certain diseases warrant a "patchette" or pachymetry grid across a wide area.

Eyecare practitioners customarily order corneal pachymetry when a patient's diseased cornea is edematous or ectatic. They also use it before LASIK to help plan the photoablation.

However, a recent study (the Ocular Hypertension Treatment Study) revealed that corneal thickness plays a significant role in glaucoma detection. Patients of certain races and those who have moderate to high myopia tend to have thinner corneas. When these patients also have glaucoma or are glaucoma suspect, treatment by the physician may vary depending on the pachymetry readings.

Applanation tonometry of an unusually thin cornea results in a false reading that's lower than the actual IOP because the resistance of the corneal tissue to indentation is less than expected. The reverse is also true: Thick corneas yield false high readings. Experts have developed conversion formulas that mathematically "adjust" the IOP for an eye with a thin cornea.

Q Is there a CPT code for corneal pachymetry?

Effective Jan. 1, 2004, Medicare assigned a regular CPT code: 76514, ophthalmic ultrasound, echography, diagnostic; corneal pachymetry, unilateral or bilateral. This describes ultrasound pachymetry but not optical pachymetry.

Before January 2004, the American Medical Association defined CPT Category III code 0025T as determination of corneal thickness (e.g., pachymetry) with interpretation and report, bilateral. Most payers, including Medicare, offer a grace period of a few months (usually January and February) when 0025T is still accepted on claims. After that, you'll need the 2004 code for ultrasound pachymetry.

Interestingly, the new CPT code for pachymetry, 76514, is defined as an ultrasound procedure. A number of devices currently on the market measure corneal thickness optically -- but these devices do not meet the definition of 76514. For optical pachymetry, use 92499, unlisted ophthalmological service or procedure.

Q Does insurance cover corneal pachymetry?

No national Medicare coverage policy for corneal pachymetry currently exists. Many Medicare carriers have published local policies (LMRPs), and most of these indicate that corneal pachymetry will be covered once in a patient's lifetime for glaucoma or glaucoma suspect. Many cover pachymetry for glaucoma suspect only, and not when a patient has already been diagnosed with glaucoma. Check your local carrier policies.

The 2004 national Medicare fee schedule allowable for 76514 is $11.59; this amount is adjusted in each area by local indices. In the special case of optical pachymetry, no Medicare fee schedule amount is defined for 92499; each claim will be adjudicated on an individual basis and payment amounts may vary.

Private insurance coverage for pachymetry varies. Many payers do cover it, with wide variations in the amount of reimbursement. A few payers don't yet cover it at all for glaucoma, and some payers bundle the test with an eye exam. You'll need to check with individual payers for coverage guidelines.

Q If insurance doesn't cover the test, can I charge the patient?

Usually. When you're dealing with a Medicare patient, explain why the test is necessary and that Medicare will likely deny the claim. Ask the patient to assume financial responsibility for the charge. Then get the patient's signature on an Advance Beneficiary Notice and submit your claim with modifier GA. You may collect your fee from the patient at the time of service, or wait for a Medicare denial. If both the patient and Medicare pay, be sure to promptly refund the patient.

As noted above, coverage policies by private insurers vary. You'll need to check with your payers to determine their payment policies -- some permit you to charge the patients while others will not.

You're going to need it

Eyecare practitioners have used corneal pachymetry for a long time for patients with edematous or ectatic conditions. Recent studies have indicated its usefulness for patients who have glaucoma or who are glaucoma suspect. So although coverage is limited, corneal pachymetry will likely prove to be a useful test when managing these diseases.


If you have a coding question you'd like answered, send it to René Luthe, c/o Optometric Management, 1300 Virginia Drive, Suite 400, Ft. Washington, PA 19034 or to


Optometric Management, Issue: March 2004