Glaucoma is a group of eye diseases that can damage the optic nerve, the structure responsible for transmitting visual information from the eye to the brain. Because some common forms of glaucoma can develop gradually without noticeable symptoms in their early stages, comprehensive eye examinations and appropriate glaucoma testing play an important role in identifying concerning changes before significant vision loss occurs.
At Northern Avenue Eye Care in Phoenix, Arizona, glaucoma evaluation may involve several tests designed to assess different aspects of eye health. Rather than relying on a single measurement, eye doctors can consider eye pressure, optic nerve appearance, visual field function, corneal characteristics, and other clinical findings when evaluating a patient’s risk.
Understanding what happens during glaucoma testing can make an upcoming eye examination easier to navigate. Here is what patients should know about common glaucoma tests, why they are performed, and what may happen if an examination reveals an abnormal result.
What Is Glaucoma Testing?
Glaucoma testing is an evaluation of the eyes for signs of glaucoma and factors associated with an increased risk of developing the disease. Depending on the patient’s needs and findings during the examination, testing may include measuring intraocular pressure, examining the optic nerve, assessing peripheral vision, measuring corneal thickness, and examining the eye’s drainage angle.
Why Is Glaucoma Testing Important?
Glaucoma can cause irreversible vision loss when optic nerve damage progresses. In many cases, a person may not notice early changes because peripheral vision can be affected gradually.
Testing is therefore important because an eye doctor may identify suspicious findings before a patient experiences obvious vision problems. Early identification also gives patients and their eye care providers an opportunity to determine whether monitoring or treatment is appropriate.
Can You Have Glaucoma Without Knowing It?
Yes. Some forms of glaucoma, particularly open-angle glaucoma, may progress without noticeable early symptoms. A person can feel that their eyesight is normal while changes are occurring to the optic nerve or visual field.
This is one reason routine comprehensive eye examinations are important even for people who are not currently experiencing vision problems.
What Happens During a Glaucoma Eye Exam?
A glaucoma evaluation can involve multiple tests. The exact combination varies according to factors such as age, medical and family history, previous examination findings, eye pressure, and the doctor’s clinical assessment.
Medical and Eye Health History
An eye examination commonly begins with questions about your health and vision history. Your eye doctor may ask about previous eye conditions, medications, health conditions, past eye injuries or surgeries, and whether glaucoma occurs in your family.
Family history can be particularly relevant because having a close relative with glaucoma may increase a person’s risk.
Patients should provide an accurate medication list and tell their eye doctor about any previous glaucoma diagnoses, elevated eye pressure, or unusual findings from past examinations.
Tonometry: Measuring Eye Pressure
Tonometry measures intraocular pressure (IOP), or the pressure inside the eye. Elevated eye pressure is an important glaucoma risk factor, although pressure measurements alone cannot determine whether someone has glaucoma.
Several methods can be used to measure IOP. With certain types of tonometry, numbing drops may be placed in the eyes before an instrument gently contacts the surface of the cornea. Other instruments measure pressure without direct contact.
The measurement itself is generally brief.
Is High Eye Pressure the Same as Glaucoma?
No. Elevated intraocular pressure does not automatically mean a person has glaucoma. Some individuals have higher-than-average eye pressure without detectable optic nerve damage, a condition often described as ocular hypertension.
Conversely, glaucoma can sometimes occur even when measured eye pressure falls within a statistically typical range.
For this reason, glaucoma assessment generally involves more than an eye pressure reading.
Optic Nerve Examination
The optic nerve is directly affected by glaucoma, making its evaluation an important part of glaucoma testing.
What Does the Eye Doctor Look for?
During an examination, an eye doctor evaluates the appearance of the optic nerve for characteristics that could indicate glaucoma or changes that warrant further investigation.
The doctor may use magnification and specialized instruments to examine the back of the eye. Dilating drops may also be used when clinically appropriate to provide a more detailed view of internal eye structures.
Why Are Repeat Examinations Important?
Glaucoma is often evaluated by looking for changes over time. Baseline measurements, photographs, scans, or other examination findings can provide a reference point for future visits.
Comparing current findings with previous results may help an eye doctor determine whether the optic nerve appears stable or whether changes have occurred.
Optical Coherence Tomography and Glaucoma
Optical coherence tomography, commonly called OCT, is a noninvasive imaging technology frequently used in glaucoma assessment.
What Does an OCT Scan Measure?
OCT can produce detailed cross-sectional images of structures in the back of the eye. In glaucoma care, it may be used to evaluate the retinal nerve fiber layer and other structures associated with the optic nerve.
The resulting measurements can help eye doctors identify patterns that may be consistent with glaucoma and monitor structural changes over time.
Does an OCT Scan Hurt?
OCT imaging is noninvasive and does not typically involve touching the eye. Patients generally look into the instrument and focus on a target while images are captured.
The scan is usually completed quickly, although additional images may be needed to obtain measurements of sufficient quality.
Visual Field Testing for Glaucoma
Glaucoma can affect peripheral vision, which may not be obvious during everyday activities in the early stages. Visual field testing evaluates how well a person sees in different areas of their field of vision.
What Happens During a Visual Field Test?
During automated visual field testing, a patient typically looks at a fixed central target while small lights appear at different locations. The patient indicates when a light is seen, often by pressing a button.
It is important to continue looking at the central target rather than trying to follow each light with your eyes.
Why Can Visual Field Tests Be Repeated?
Visual field testing requires concentration, and results can sometimes vary because of fatigue, attention, learning effects, or other factors. An unusual result does not necessarily establish that glaucoma is present.
Repeating the test can help an eye doctor determine whether a suspected visual field pattern is reproducible and whether meaningful changes occur over time.
Pachymetry: Measuring Corneal Thickness
Pachymetry measures the thickness of the cornea, the clear front surface of the eye.
Why Does Corneal Thickness Matter in Glaucoma Testing?
Corneal thickness can affect the interpretation of intraocular pressure measurements. It may also contribute additional information to a patient’s overall glaucoma risk assessment.
Because glaucoma evaluation involves interpreting multiple findings together, knowing corneal thickness can help provide useful clinical context.
Is Pachymetry Uncomfortable?
Pachymetry is typically a quick test. Depending on the technology used, measurement may be performed with an instrument that gently contacts the cornea after numbing drops are administered or with a non-contact device.
Gonioscopy: Examining the Eye’s Drainage Angle
The eye continuously produces and drains fluid. The area where this fluid exits the eye is known as the anterior chamber angle or drainage angle.
Gonioscopy allows an eye doctor to examine this area and can help distinguish between different glaucoma mechanisms.
What Happens During Gonioscopy?
After numbing drops are applied, the doctor may gently place a specialized lens on the eye. The lens provides a view of the drainage angle that cannot be adequately assessed simply by looking at the eye from the outside.
Patients may notice the lens touching the eye, but the anesthetic drops are intended to minimize discomfort.
Do Your Eyes Need to Be Dilated for Glaucoma Testing?
Dilation may be part of a comprehensive glaucoma evaluation because it can help an eye doctor examine the optic nerve and other structures inside the eye.
Not every glaucoma-related test requires dilation, however. Your eye doctor can determine which examination methods are appropriate for your circumstances.
After dilation, some patients experience temporary light sensitivity and blurred near vision. The duration varies depending on the drops used and individual response.
How Long Does Glaucoma Testing Take?
There is no universal duration for a glaucoma evaluation because the number and type of tests can vary.
A routine comprehensive examination may include some glaucoma screening components, while a patient with suspicious findings or an established glaucoma diagnosis may require additional imaging, visual field testing, or other procedures.
When scheduling your appointment, you can ask the office whether specialized testing is anticipated and how much time you should allow.
Who Should Be Evaluated for Glaucoma?
Glaucoma testing recommendations should be individualized based on a person’s age, eye health, medical history, examination findings, and risk factors.
What Factors Can Increase Glaucoma Risk?
Factors that may be relevant to glaucoma risk include increasing age, family history of glaucoma, elevated intraocular pressure, certain anatomical characteristics of the eye, previous eye injuries, and some medical conditions or medication exposures.
Having one or more risk factors does not mean that glaucoma will necessarily develop. Instead, these factors can help an eye doctor determine the appropriate type and frequency of examination.
What Happens If a Glaucoma Test Is Abnormal?
An abnormal result does not always mean that a person definitively has glaucoma.
An eye doctor may repeat a test, compare the result with previous measurements, perform additional testing, or recommend follow-up examinations. Glaucoma diagnosis is based on the overall clinical picture rather than one isolated result.
What Is a Glaucoma Suspect?
The term “glaucoma suspect” may be used when a patient has one or more findings that raise concern for glaucoma but does not yet meet the criteria for a definitive diagnosis.
For example, a patient may have elevated eye pressure, an optic nerve appearance that warrants observation, or another relevant risk factor. Regular monitoring can help determine whether changes develop over time.
What If Glaucoma Is Diagnosed?
The goal of glaucoma treatment is generally to reduce the risk of additional optic nerve damage and preserve remaining vision. Treatment recommendations depend on the type and severity of glaucoma, eye pressure, disease progression, and other individual considerations.
Management can include prescription eye drops, laser procedures, surgical approaches, or a combination of treatments. Your eye care provider can explain which options are appropriate for your diagnosis.
Because vision already lost from glaucoma generally cannot be restored, ongoing monitoring and adherence to a recommended treatment plan are important.
How to Prepare for Glaucoma Testing
Preparing for an eye examination is usually straightforward. Bring your current eyeglasses or contact lens information, a list of medications and supplements, relevant medical information, and details about your family’s eye health history when available.
If you have undergone previous glaucoma testing elsewhere, bringing prior examination records, visual field results, optic nerve images, or OCT scans may be helpful. Historical results can allow your eye doctor to evaluate whether meaningful changes have occurred over time.
If dilation is expected, consider asking the office beforehand how it could affect activities such as driving or returning to work.
Glaucoma Testing in Phoenix, AZ
Regular eye examinations can help identify glaucoma risk factors and detect changes that may otherwise go unnoticed. Because glaucoma evaluation considers several aspects of eye health, an examination may include eye pressure measurement, optic nerve assessment, visual field testing, imaging, corneal measurements, and other testing when appropriate.
Northern Avenue Eye Care serves patients in Phoenix, Arizona, and can evaluate your eye health and determine which testing is appropriate based on your individual findings and risk factors.
If you are due for an eye examination, have a family history of glaucoma, have previously been told that your eye pressure is elevated, or have questions about glaucoma testing, schedule an appointment with Northern Avenue Eye Care.
Frequently Asked Questions About Glaucoma Testing
Is a glaucoma test painful?
Most routine glaucoma tests are noninvasive or minimally invasive and are designed to cause little discomfort. Numbing drops may be used for tests that involve contact with the surface of the eye.
Can glaucoma be detected during a routine eye exam?
A comprehensive eye examination can identify findings associated with glaucoma. If something appears suspicious, an eye doctor may recommend additional testing to evaluate the optic nerve, visual field, eye pressure, drainage angle, or other characteristics.
Is the air-puff test enough to diagnose glaucoma?
No. An air-puff test is one method of estimating intraocular pressure, but glaucoma cannot generally be diagnosed from a single pressure measurement. Optic nerve health, visual function, risk factors, and other examination findings may also need to be evaluated.
Can I have normal eye pressure and still have glaucoma?
Yes. Glaucomatous optic nerve damage can occur in some people whose measured eye pressure is within a statistically typical range. Eye pressure is therefore only one component of glaucoma assessment.
Does high eye pressure always mean I have glaucoma?
No. Some people have elevated intraocular pressure without detectable glaucomatous optic nerve damage. Your eye doctor can evaluate the complete clinical picture and recommend appropriate monitoring or treatment.
What is the most important test for glaucoma?
There is not necessarily one test that provides every piece of information needed to evaluate glaucoma. Eye pressure measurements, optic nerve examination and imaging, visual field testing, corneal thickness, drainage-angle assessment, and longitudinal changes can all provide useful information.
How often should I be tested for glaucoma?
The appropriate examination interval depends on individual risk factors and previous findings. Someone with suspicious optic nerve findings or elevated eye pressure may need a different follow-up schedule than a person without known risk factors. Your eye doctor can recommend an examination schedule based on your circumstances.
Can glaucoma testing detect vision loss before I notice it?
Testing can sometimes identify structural or functional abnormalities before a patient recognizes changes during everyday activities. This is one reason appropriate routine eye examinations are valuable.
Why does my eye doctor want to repeat my visual field test?
Visual field results can be influenced by attention, fatigue, familiarity with the test, and other factors. Repeating a test may help determine whether an abnormal finding is consistent and reproducible.
What should I do if glaucoma runs in my family?
Tell your eye doctor about your family history, including which relatives have been diagnosed if you know. Family history can influence an individual’s risk assessment and may affect recommendations for monitoring.
Can glaucoma-related vision loss be reversed?
Vision loss caused by glaucomatous optic nerve damage is generally considered irreversible. Treatment focuses on reducing the risk of further damage and preserving remaining vision, which makes timely evaluation and appropriate follow-up important.
Will my eyes be dilated during glaucoma testing?
They may be. Dilation can allow a more detailed examination of the optic nerve and retina, although not every glaucoma test requires dilated pupils. Your eye doctor will determine whether dilation is appropriate.
How can I schedule a glaucoma eye exam in Phoenix?
Patients can contact Northern Avenue Eye Care at (602) 995-8848 or use the practice’s online appointment scheduling page to request an appointment. The office is located at 2337 W Northern Ave in Phoenix, Arizona.
Contact Information
Northern Avenue Eye Care
2337 W Northern Ave
Phoenix, AZ 85021
Phone: (602) 995-8848
Website: northernaveeyecare.com
Schedule An Appointment: northernaveeyecare.com/appointments/