Tonometry

Eye pressure measurement is most often done with a tool called a tonometer ( Some eye doctors use something called “air puff tonometry” instead of the Goldmann tonometry method described above. The air puff is not as accurate but can be used as a screening tool. Other ways to measure the eye pressure that are not routinely done any longer will be briefly mentioned here: Pneumotonometry involves using a diaphragm connected to a gas filled chamber to measure the eye pressure, and in Schiotz tonometry, the indentation of the cornea by an object of known weight gives an estimation of eye pressure. Figure 10: Goldmann tonometer. Drawing shows how the Goldmann applanation tonometer rests against and flattens the cornea to measure eye pressure. (Right) Photograph of the tonometer with its tip (top of instrument) that contacts the cornea. Courtesy of William Ricky Buie, COT. Tonometry is usually easy to go through, since the eye has been numbed by drops, so you feel nothing. During the actual measurement, the instrument can rub some cells from the cornea if it is not done gently. If the patient rubs his or her eye during the 20 minutes afterward, the cornea can also be scratched. This rarely happens, but can cause substantial pain or a feeling like something is in the eye. The doctor should be made aware if this happens. Pressure was originally measured using the change in a column of mercury that we now only see in temperature thermometers. Although the instruments have changed, ...

Our eyes constantly make a fluid called As part of a In the past, you may have had an eye pressure test using a puff of air. Now most ophthalmologists use a more accurate device that measures pressure by direct contact with the eye. How Is Eye Pressure Measured? • Eye drops are put in your eyes to numb them. • Then the doctor or assistant gently touches the front surface of your eye with a device that glows with a blue light. Other times a different handheld instrument is used. • Both methods apply a small amount of pressure to the eye. • This allows your ophthalmologist to measure the pressure inside each eye. • During this test, it is very helpful to relax and breathe normally. Each person's eye pressure is different, and there is no single correct pressure for everyone. Generally, the range for normal pressure is between 10 and 21 mmHg ("mmHg" means "millimeters of mercury," a scale used to record eye pressure). Most people who have glaucoma will have an eye pressure higher than 21 mmHg. However, some people with pressures between 10 and 21 mmHg may have glaucoma. Your ophthalmologist will determine the eye pressure range that is healthy specifically for you.

Tonometry is a test that is commonly performed during a routine eye check-up. A tonometry test may be done by an optometrist or by an ophthalmologist. This test measures intraocular pressure (the pressure inside the eye). Intraocular pressure that is higher than normal is an important indicator of certain diseases, such as Who Needs a Tonometry Test? The American Optometric Association recommends that healthy adults between the ages of 18 and 50 receive an eye exam at least every two years. For those over the age of 50, an annual eye exam is recommended. Pediatric patients should receive a thorough eye exam before the age of 2, at about age 3, when in the first grade, and every two years to five years thereafter. More frequent exams or re-evaluation could be necessary for children who are at risk for any hereditary eye conditions. A tonometry test is recommended for all adults during routine eye exams, unless there is a contraindication. Tonometry may be postponed if there is an eye injury or if there is an ulcer on the cornea. Children are not typically given a tonometry test, unless they have had surgery to repair a Why Tonometry Is Done Tonometry is a relatively simple test that can screen for diseases such as glaucoma, for which high intraocular pressure is a risk factor. Glaucoma, if left untreated, can lead to Preparing for a Tonometry Test In general, there is no special preparation needed for a tonometry test. The patient must take out their contact lenses before i...

Glaucoma is a disease in which the nerve of the eye (the optic nerve) is gradually damaged over time, resulting in a loss of vision. This disease is often associated with increased eye pressure. Identifying this elevated eye pressure and trying to lower it is the only known way to prevent blindness from glaucoma. Early screening can help protect your Why Do I Need This Test? Your Sometimes the pressure is caused by an eye injury or trauma. Once your eye heals, everything may go back to normal. But some people have a drainage system that doesn’t work like it should. Over time, high pressure inside your eye can damage your optic nerve, which sends images from your eyes to your Since the disease usually does not have symptoms, regular eye exams are a good idea. Your eye doctor will check your eye pressure by doing a tonometry test. They can also track any changes in pressure over time. Anyone can get glaucoma, but your odds are higher if you: • Are over 40 • Have a family member with glaucoma • Are African, Hispanic or Asian • Have had an eye injury • Are far-sighted or near-sighted • Have been told your corneas are thin in the middle • Have • Get • Have circulation ( What Happens During a Tonometry Test? Your doctor can check your eye pressure in a couple of different ways: • Tonometer/ Applanation . After special numbing drops are put in your eye, your doctor gently holds this pencil-shaped device against the outside of your eyeball. The reading tells how well your • “Puff ...

Tonometry • • What is the test? Tonometry is a test to measure pressure in your eyeball. High pressure inside the eye is caused by a disease called glaucoma, which can damage your vision if it is not treated. How do I prepare for the test? Remove any contact lenses. Tell your doctor if you have an eye infection or other type of eye problem. What happens when the test is performed? The pressure inside your eye is always measured from the outside. In most cases, if you are at an eye clinic, the pressure can even be measured without anything actually touching your eye. The eye doctor has you look up close at an instrument that blows a small puff of air onto your eye. It then uses a special sensor (like a tiny radar detector) to detect the amount of indentation that the air puff causes on the surface of the eye. This indentation is normal and lasts for only a fraction of a second. Sometimes patients need to have their eye pressure measured but they are not in an eye clinic with this type of machine (for example, some patients need to be checked for glaucoma in an emergency room). In this case, the pressure can be measured with an instrument resembling a pen. One end of the instrument is placed on the surface of the eyeball. This feels like having a contact lens put in your eye. What risks are there from the test? The test might make you feel like blinking, but it does not cause any pain. There are no risks from this test. Must I do anything special after the test is over? No. ...

Although a connection between eye firmness and blindness was recorded as far back as the 1600s, we still have no perfect method to measure intraocular pressure (IOP); all current methods are influenced by various ocular and non-ocular factors and can only give us an estimate of the intraocular pressure. Accurate and precise IOP readings are imperative to evaluate a patient’s risk of progressive optic nerve damage. Inaccurate or inconsistent IOP measurements prevent the clinician from making accurate treatment and management decisions and may put the patient at risk for visual field loss. Clinicians need to develop a consistent, reproducible and reliable technique for obtaining IOP measurements so that they can be compared with confidence over time. When holding the patient’s lids open, don’t inadvertently apply pressure to the globe. Here are some helpful recommendations to keep in mind when measuring a patient’s IOP (unless otherwise noted, recommendations relate to Goldmann applanation tonometry, GAT): DO consider the patient’s position, comfort and clothing prior to checking IOP. Make sure to position the patient correctly in the slit lamp without discomfort. The head and chin should be in contact with the forehead and chin rests and the lateral canthi should be aligned with the line on the slit lamp’s frame. Encourage the patient to breathe normally. It’s common for patients to hold their breath out of anxiety, poor positioning, or both, during an IOP measurement. This...

Tonometry • • What is the test? Tonometry is a test to measure pressure in your eyeball. High pressure inside the eye is caused by a disease called glaucoma, which can damage your vision if it is not treated. How do I prepare for the test? Remove any contact lenses. Tell your doctor if you have an eye infection or other type of eye problem. What happens when the test is performed? The pressure inside your eye is always measured from the outside. In most cases, if you are at an eye clinic, the pressure can even be measured without anything actually touching your eye. The eye doctor has you look up close at an instrument that blows a small puff of air onto your eye. It then uses a special sensor (like a tiny radar detector) to detect the amount of indentation that the air puff causes on the surface of the eye. This indentation is normal and lasts for only a fraction of a second. Sometimes patients need to have their eye pressure measured but they are not in an eye clinic with this type of machine (for example, some patients need to be checked for glaucoma in an emergency room). In this case, the pressure can be measured with an instrument resembling a pen. One end of the instrument is placed on the surface of the eyeball. This feels like having a contact lens put in your eye. What risks are there from the test? The test might make you feel like blinking, but it does not cause any pain. There are no risks from this test. Must I do anything special after the test is over? No. ...

Our eyes constantly make a fluid called As part of a In the past, you may have had an eye pressure test using a puff of air. Now most ophthalmologists use a more accurate device that measures pressure by direct contact with the eye. How Is Eye Pressure Measured? • Eye drops are put in your eyes to numb them. • Then the doctor or assistant gently touches the front surface of your eye with a device that glows with a blue light. Other times a different handheld instrument is used. • Both methods apply a small amount of pressure to the eye. • This allows your ophthalmologist to measure the pressure inside each eye. • During this test, it is very helpful to relax and breathe normally. Each person's eye pressure is different, and there is no single correct pressure for everyone. Generally, the range for normal pressure is between 10 and 21 mmHg ("mmHg" means "millimeters of mercury," a scale used to record eye pressure). Most people who have glaucoma will have an eye pressure higher than 21 mmHg. However, some people with pressures between 10 and 21 mmHg may have glaucoma. Your ophthalmologist will determine the eye pressure range that is healthy specifically for you.

Glaucoma is a disease in which the nerve of the eye (the optic nerve) is gradually damaged over time, resulting in a loss of vision. This disease is often associated with increased eye pressure. Identifying this elevated eye pressure and trying to lower it is the only known way to prevent blindness from glaucoma. Early screening can help protect your Why Do I Need This Test? Your Sometimes the pressure is caused by an eye injury or trauma. Once your eye heals, everything may go back to normal. But some people have a drainage system that doesn’t work like it should. Over time, high pressure inside your eye can damage your optic nerve, which sends images from your eyes to your Since the disease usually does not have symptoms, regular eye exams are a good idea. Your eye doctor will check your eye pressure by doing a tonometry test. They can also track any changes in pressure over time. Anyone can get glaucoma, but your odds are higher if you: • Are over 40 • Have a family member with glaucoma • Are African, Hispanic or Asian • Have had an eye injury • Are far-sighted or near-sighted • Have been told your corneas are thin in the middle • Have • Get • Have circulation ( What Happens During a Tonometry Test? Your doctor can check your eye pressure in a couple of different ways: • Tonometer/ Applanation . After special numbing drops are put in your eye, your doctor gently holds this pencil-shaped device against the outside of your eyeball. The reading tells how well your • “Puff ...

Tonometry is a test that is commonly performed during a routine eye check-up. A tonometry test may be done by an optometrist or by an ophthalmologist. This test measures intraocular pressure (the pressure inside the eye). Intraocular pressure that is higher than normal is an important indicator of certain diseases, such as Who Needs a Tonometry Test? The American Optometric Association recommends that healthy adults between the ages of 18 and 50 receive an eye exam at least every two years. For those over the age of 50, an annual eye exam is recommended. Pediatric patients should receive a thorough eye exam before the age of 2, at about age 3, when in the first grade, and every two years to five years thereafter. More frequent exams or re-evaluation could be necessary for children who are at risk for any hereditary eye conditions. A tonometry test is recommended for all adults during routine eye exams, unless there is a contraindication. Tonometry may be postponed if there is an eye injury or if there is an ulcer on the cornea. Children are not typically given a tonometry test, unless they have had surgery to repair a Why Tonometry Is Done Tonometry is a relatively simple test that can screen for diseases such as glaucoma, for which high intraocular pressure is a risk factor. Glaucoma, if left untreated, can lead to Preparing for a Tonometry Test In general, there is no special preparation needed for a tonometry test. The patient must take out their contact lenses before i...