Glaucoma is a group of eye diseases that damage the optic nerve, which is vital for good vision. This damage is often caused by an abnormally high pressure in your eye. Glaucoma is one of the leading causes of blindness for people over 60 years old. Early detection and treatment are key to stopping the progression of glaucoma.
The most common tests used to detect glaucoma and confirm the diagnosis are:
Eye Pressure Test (Tonometry)
This test measures your eye pressure using a tonometer. Numbing eye drops may be applied before the test. Your doctor will then gently place the tonometer tip against your eye to measure the pressure inside. Normal eye pressure ranges between 10-21 mm Hg. Higher eye pressure means you are more at risk for developing glaucoma damage. However, some people can develop glaucoma even with normal eye pressure.
Visual Field Test
A visual field test checks for missing areas in your peripheral or side vision. You’ll be asked to click a button whenever you see a flashing light on a screen in front of you. Vision loss begins with side vision, so this helps detect glaucoma early.
Ophthalmoscopy
This test allows your doctor to see inside your eye, including the optic nerve. Pupil dilating eyedrops are applied so your doctor can examine the optic nerve for signs of damage using a slit-lamp microscope with a special lens called an ophthalmoscope.
Optical Coherence Tomography (OCT)
OCT uses light waves to take a detailed picture of your retina and optic nerve. This shows the thickness and health of the nerve fibers and can help confirm a glaucoma diagnosis.
Gonioscopy
This diagnostic test uses a special contact lens called a goniolens. It allows your doctor to see inside the front part of your eye and examine the angle where the iris meets the cornea. The angle needs to drain fluid properly so if it’s too narrow or closed, pressure can build.
Key Signs and Symptoms
Glaucoma develops slowly over time, often without symptoms until significant vision loss has occurred. The most common signs and symptoms include:
- Gradual loss of peripheral or side vision
- Tunnel vision
- Frequent changes in eyeglass prescription
- Redness or pain in the eyes
- Nausea or vomiting
- Seeing halos around lights
- Headache or eye pain
Since glaucoma causes gradual vision changes, many people adapt without realizing their vision is shrinking. Regular eye exams are essential to detect glaucoma early before major vision loss occurs.
People at High Risk
There are several factors that put you at increased risk for developing glaucoma:
- Being over age 60
- Having a family history of glaucoma
- Being of African, Asian, or Hispanic descent
- Having high eye pressure (over 21 mm Hg)
- Being farsighted or nearsighted
- Having past eye injuries, inflammation, or surgery
- Taking steroid medications like prednisone
- Having diabetes, heart disease, or high blood pressure
Talk to your doctor about your glaucoma risk if you have any of these factors. They may recommend more frequent eye exams to screen for glaucoma. Catching it early provides the best opportunity to prevent vision loss.
Types of Glaucoma
There are two main categories of glaucoma:
Open-Angle Glaucoma
This is the most common type of glaucoma in the United States. It develops slowly over time and is caused by the eye’s drainage canals becoming clogged. This prevents fluid from draining properly and leads to increased eye pressure. There are usually no symptoms until major vision loss has occurred.
Angle-Closure Glaucoma
This less common type of glaucoma is caused when the drainage angle of the eye becomes completely blocked or closed. It leads to a rapid, sudden increase in eye pressure. Symptoms come on quickly and can include eye redness, blurred vision, headache, rainbow halos around lights, severe eye pain, nausea, and vomiting. This is a medical emergency since permanent vision loss can occur within days.
Diagnosing Glaucoma
An eye doctor can diagnose glaucoma using the following steps:
- Taking a complete medical history to identify glaucoma risks
- Checking eye pressure with tonometry
- Examining optic nerve damage with ophthalmoscopy
- Evaluating peripheral vision loss with visual field testing
- Taking detailed photos of the optic nerve and retina with OCT imaging
- Inspecting the drainage angle with gonioscopy
Based on these test results and a thorough exam, your doctor will determine if you have glaucoma. They may also perform tests to look for other eye conditions with similar symptoms.
Glaucoma Severity Classifications
To guide treatment, glaucoma is classified by stages based on optic nerve damage and visual field loss:
| Stage | Description |
|---|---|
| Early (Mild) Glaucoma | Optic nerve damage and mild visual field loss |
| Moderate Glaucoma | Increasing optic nerve damage and visual field loss |
| Severe (Advanced) Glaucoma | Severe optic nerve damage and visual field loss threatening central vision |
Identifying and treating glaucoma in the early stages provides the best opportunity to slow disease progression and prevent blindness.
Is More Testing Needed?
Your eye doctor may want to repeat some tests over time to monitor for any changes signalling glaucoma progression. They may also recommend referral to a glaucoma specialist (ophthalmologist) for additional diagnostic testing in complex cases.
Further testing that could provide more definitive glaucoma confirmation includes:
- Fluorescein angiography: Dye is injected into the arm to trace blood flow in retinal blood vessels and look for defects.
- Slit lamp exam: A slit lamp microscope provides highly magnified view of the drainage angle and optic nerve.
- Retinal photography: Detailed photos document the optic nerve and retina appearance.
- Corneal pachymetry: Measures central corneal thickness which can influence eye pressure readings.
- Visual evoked potential: Electrodes measure brain wave response to visual stimuli, which can detect optic nerve damage.
These advanced tests provide additional insights to guide diagnosis and treatment decisions.
Treatment Options
Glaucoma treatment focuses on lowering eye pressure to slow the progression of nerve damage and vision loss. Treatment options include:
Medicated Eye Drops
Eyedrops are typically the first line treatment. Different types of prescription drops help lower eye pressure by either decreasing fluid production or improving drainage:
- Prostaglandins increase fluid outflow
- Beta blockers reduce fluid production
- Alpha agonists also reduce fluid production
- Carbonic anhydrase inhibitors slow fluid secretion into the eye
Using the drops properly is key to their effectiveness. Most people need to use glaucoma drops daily for life.
Oral Medications
Oral prescription carbonic anhydrase inhibitors like methazolamide (Neptazane) or acetazolamide (Diamox) can also be used to decrease fluid production and eye pressure.
Laser Trabeculoplasty
This office-based laser procedure can open up the drainage canals to allow better fluid outflow and pressure reduction. It is often done first before trying drops or surgery.
Glaucoma Surgery
Surgery may be recommended if medications and laser treatment are not enough to slow glaucoma progression and prevent vision loss. Surgery creates a new drainage pathway or shunt to improve outflow. Common glaucoma surgeries include trabeculectomy and drainage tube shunt implantation.
Follow-up Care is Critical
Ongoing follow-up care is required to monitor glaucoma progression and adjust treatments. After the initial diagnostic exams, your ophthalmologist will determine a follow-up schedule with repeat testing:
- Eye exam and eye pressure check every 6-12 months
- Visual field testing every 6-24 months
- Optic nerve imaging tests every 6-24 months
The eye exam frequency varies based on glaucoma type, severity, risk factors, and rate of progression. Early detection of disease progression is essential to prevent vision loss.
Tips for Living with Glaucoma
Steps you can take to successfully manage glaucoma include:
- Using all medications properly and consistently
- Keeping all follow-up appointments for repeat testing
- Reporting any new symptoms like eye pain or vision changes
- Maintaining a healthy diet and exercise routine
- Wearing sunglasses to protect your eyes outdoors
- Avoiding certain medications that can worsen glaucoma
- Learning more about your type of glaucoma and treatment options
Joining a glaucoma support group can also provide education and encouragement in managing your condition. Early, active treatment gives you the best chance of preserving your vision and independence.
Conclusion
Confirming a glaucoma diagnosis involves specialized eye tests like tonometry, visual field testing, ophthalmoscopy, and optic nerve imaging. Detecting glaucoma in its early stages is key to successful treatment and preventing vision disability through increased eye pressure damaging the optic nerve. With proper ongoing care and adherence to glaucoma treatment, it is possible to slow disease progression and vision loss. Consistent follow up care is necessary to monitor for progression and adjust treatments accordingly. Glaucoma can be challenging to manage, but early diagnosis combined with the latest medical, laser, and surgical options provide the best opportunity for maintaining lifelong vision health.