If a routine eye exam shows that your eye pressure is higher than normal, your eye doctor may want to know whether your cornea is influencing that number. A thicker cornea can make your pressure appear higher than it truly is inside the eye. Pachymetry helps separate a real pressure concern from one caused by corneal thickness alone.
Glaucoma often runs in families. If a parent, sibling, or grandparent has been diagnosed, your risk is higher than average. Your eye doctor may recommend corneal thickness testing as part of a more thorough risk assessment. Knowing your corneal thickness alongside your pressure reading gives a clearer picture of where you stand and whether closer monitoring is needed.
Procedures like laser vision correction reshape the cornea to improve focus. These procedures work by removing a thin layer of corneal tissue. Your eye doctor needs to know how much tissue is available before referring you for surgery. Pachymetry provides that measurement so the surgical team can plan safely and confirm that your cornea has enough thickness to support the procedure.
Conditions like keratoconus cause the cornea to thin and change shape over time. Tracking corneal thickness helps your eye doctor monitor whether the condition is stable or progressing. This information guides decisions about contact lens fitting, cross-linking referrals, and long-term management. Patients in Las Vegas, Henderson, and surrounding areas who are managing corneal conditions benefit from having pachymetry as part of their regular follow-up care.
Think of your cornea like the crystal on a watch. It is a thin, clear dome that protects the inside of your eye and bends light so you can see. The average cornea is roughly 540 to 560 micrometers thick. That is about half a millimeter. A small difference in thickness from one person to the next can change how pressure instruments register your reading.
When you measure pressure by pressing against the cornea, a thicker cornea resists more and gives a higher number. A thinner cornea resists less, so the number comes out lower. Neither reading is wrong on its own. It just needs context, and pachymetry provides that missing piece of the puzzle.
Corneal pachymetry uses sound waves or light to measure your cornea from front to back. In the most common version, called ultrasound pachymetry, your eye doctor places a small probe gently against your cornea after numbing it with a drop. The probe sends a sound wave through the cornea and measures how long it takes to bounce back. The whole process takes just a few seconds per eye and produces an instant reading.
Some practices also use light-based imaging to map corneal thickness across the entire surface. These instruments capture a cross-section image of the cornea without touching the eye at all.
At Insight Vision Optometry, Las Vegas, our eye doctors use advanced anterior segment imaging and corneal mapping technology. These tools can measure thickness at thousands of points across the cornea. That gives our team a detailed picture of your corneal shape and structure, which is especially useful for managing conditions like keratoconus.
The landmark Ocular Hypertension Treatment Study, published in the Archives of Ophthalmology, followed over 1,600 patients with elevated eye pressure. The study found that patients with corneas measuring 555 micrometers or thinner had three times the risk of developing glaucoma within five years compared to patients with thicker corneas. Corneal thickness turned out to be one of the strongest predictors of who would go on to develop actual glaucoma damage.
According to data highlighted by the Glaucoma Research Foundation, 36 percent of high-risk patients with both elevated eye pressure and thin corneas developed glaucoma at five years. According to the same analysis, only 6 percent of patients with the same elevated pressure but thicker corneas progressed to glaucoma. The same pressure number meant very different things depending on corneal thickness.
These findings changed how eye doctors evaluate glaucoma risk. A pressure reading alone is not enough. When your eye doctor factors in corneal thickness, they get a more accurate picture of what is happening inside your eye. Results can vary from person to person, and no single number tells the whole story. Your eye doctor will interpret your pachymetry measurement alongside your full exam findings to determine the best plan for you.
There is no special preparation needed for most patients. You do not need to stop wearing contact lenses beforehand for a standard pachymetry reading. However, your eye doctor may give you specific instructions if the measurement is part of a surgical evaluation. The test is often done during a routine comprehensive eye exam, so you may not even know it is coming until your doctor adds it to your visit.
Your eye doctor or technician will place a numbing drop in each eye. You will feel the drop go in, but after a few seconds the surface of your eye will be comfortably numb. For ultrasound pachymetry, a small, pen-sized probe touches the center of your cornea very lightly. You may feel a gentle tap, but it is not painful. The measurement takes just a few seconds per eye.
If your eye doctor uses a non-contact imaging method, you simply look into the instrument while it scans. There is no probe and no contact with the eye at all.
The numbing drop wears off within about 15 to 20 minutes. There are no restrictions afterward. Your eye doctor will review your corneal thickness alongside your pressure reading and other test results. This gives you a complete picture of your eye health. If your cornea is thinner than average, your doctor may adjust how they interpret your pressure or recommend more frequent monitoring.
Your visit starts with a thorough eye exam. This includes eye pressure measurement, a detailed look at the front and back of your eye, and any other tests your eye doctor thinks are important based on your history. If there is a reason to check your corneal thickness, your doctor will include pachymetry in that visit.
The pachymetry test itself is quick and comfortable. Our eye doctors in Las Vegas use both contact and non-contact methods depending on what gives the best information for your situation. If you are being evaluated for a corneal condition like keratoconus, your doctor may also map the thickness across your entire cornea to look for patterns of thinning.
Once your corneal thickness measurement is complete, your eye doctor reviews it alongside your pressure, optic nerve appearance, visual field results, and any imaging. This combined picture is what determines your actual risk level. Your doctor will explain what the numbers mean for you and whether any follow-up is recommended.
For patients in Spring Valley, Henderson, Enterprise, Paradise, and across the Las Vegas valley, our team provides ongoing monitoring when corneal thickness or eye pressure warrants closer attention. If your results suggest elevated glaucoma risk, your doctor will set up a schedule for regular check-ins so any changes are caught early.
Not at all. Your eye doctor uses a numbing drop before the test, so you will not feel pain. The ultrasound method involves a light touch on the surface of your eye that most patients barely notice. The non-contact method does not touch your eye at all. The entire process takes only a few seconds per eye.
For most patients, a single measurement is enough because corneal thickness does not change much over time in a healthy eye. However, if you have a condition that affects the cornea, such as keratoconus, your eye doctor may repeat the measurement periodically to track any changes. Patients being monitored for glaucoma risk may also have the test repeated as part of their regular follow-up.
There is currently no treatment that increases corneal thickness. Having a thin cornea is not a disease. It is a natural variation, like height. What matters is how your eye doctor uses that information. If your cornea is thin, your doctor may adjust how they interpret your eye pressure and may monitor you more closely for signs of glaucoma.
They measure different things. Pachymetry measures how thick your cornea is from front to back. Topography maps the surface shape of your cornea, showing curves, flat spots, and irregularities. Both tests are painless and quick. Your eye doctor may use them together to get a full picture of your corneal health. This is especially common if you have keratoconus or are being evaluated for laser vision correction.
The average corneal thickness falls between 540 and 560 micrometers, or roughly half a millimeter. Corneas thinner than about 520 micrometers are generally considered thin. Corneas thicker than about 580 micrometers are considered thick. These are not rigid cutoffs. Your eye doctor will interpret your measurement in the context of your overall eye health.
Contact lens wear can temporarily change corneal thickness. This is especially true with rigid or scleral lenses that vault over the cornea. For routine pachymetry during a standard eye exam, this is usually not a concern. If your eye doctor needs the most precise measurement possible, such as for a surgical evaluation, they may ask you to leave your lenses out for a specific period before the test. Your doctor at Insight Vision Optometry will give you clear instructions based on your lens type and the reason for the measurement.
