Understanding Glaucoma
What is Glaucoma?
Glaucoma is a group of eye conditions that damage the optic nerve, which is vital for good vision.
This damage is often caused by abnormally high pressure in your eye, though not always.
Glaucoma is one of the leading causes of blindness for people over 60, but
blindness from glaucoma can often be prevented with early treatment.
How Your Eye Works
To understand glaucoma, it helps to know how your eye works:
Your eye constantly produces a clear fluid called aqueous humor that flows through
the front portion of your eye. This fluid nourishes the eye and helps maintain its shape.
In a healthy eye, the fluid flows through a mesh-like channel and drains out of the eye.
If this drainage system doesn't work properly, fluid builds up, causing increased pressure
inside the eye.
This increased pressure, called intraocular pressure (IOP), can damage the optic nerve—a
bundle of more than a million nerve fibers that carries visual information from your eye to your brain.
As the nerve fibers die, blind spots develop in your visual field. If the entire optic nerve is
destroyed, blindness results.
Types of Glaucoma
There are several types of glaucoma, but the two main types are:
Primary Open-Angle Glaucoma
This is the most common type of glaucoma. It happens gradually, where the eye does not drain fluid as
well as it should (like a clogged drain). As a result, eye pressure builds and starts to damage the optic nerve.
This type of glaucoma is painless and causes no vision changes at first.
Angle-Closure Glaucoma
This occurs when the iris (the colored part of your eye) is very close to the drainage angle, blocking fluid
from draining out of the eye. This can happen suddenly (acute) with symptoms including eye pain, headaches,
nausea, and blurred vision—this is a medical emergency. It can also happen gradually (chronic) with no symptoms until damage is severe.
To learn more about the different types of glaucoma, please see our Types of Glaucoma guide.
Symptoms of Glaucoma
Warning: Most People Don't Notice Early Symptoms
For most people, there are no early symptoms of glaucoma. Vision stays normal and there is no pain.
By the time you notice vision changes, the damage is often quite advanced.
Open-Angle Glaucoma Symptoms:
- Patchy blind spots in your peripheral (side) vision, often in both eyes
- Tunnel vision in the advanced stages
Acute Angle-Closure Glaucoma Symptoms:
- Severe eye pain
- Nausea and vomiting
- Sudden blurry vision
- Halos around lights
- Red eyes
- Headache
If you experience these symptoms, seek immediate medical attention at the nearest emergency department.
Who Is at Risk for Glaucoma?
While anyone can develop glaucoma, some people are at higher risk:
- Age: People over 60 (over 40 for African, Caribbean, or Hispanic heritage)
- Family history: Glaucoma tends to run in families
- Ethnic background: African, Caribbean, and Hispanic people have higher risk
- Medical conditions: Diabetes, heart disease, high blood pressure
- Eye conditions: High eye pressure, extreme near or farsightedness, previous eye injury or surgery
- Long-term steroid use: Especially eye drops
- Thin corneas: Having corneas thinner than average
How Is Glaucoma Diagnosed?
Glaucoma is detected through a comprehensive eye examination. Mr. Panos may perform several tests:
-
Measuring intraocular pressure (Tonometry):
Using a special instrument to measure pressure inside your eye.
-
Testing for optic nerve damage:
Examining your optic nerve for damage with special instruments.
-
Checking your visual field:
Testing your peripheral (side) vision for blind spots.
-
Measuring corneal thickness (Pachymetry):
Determining the thickness of your cornea, as thin corneas can increase risk.
-
Examining drainage angle (Gonioscopy):
Looking at the drainage angle in your eye to determine the type of glaucoma.
-
OCT scanning:
Using optical coherence tomography to create detailed images of your retina and optic nerve.
Treating Glaucoma
While damage caused by glaucoma cannot be reversed, treatment can help stop further damage. Treatment aims to lower eye pressure by:
1. Eye Drops
Most people with glaucoma are treated with prescription eye drops that:
- Reduce the production of fluid in your eye
- Increase the outflow of fluid from your eye
- Or both
These drops need to be used regularly as prescribed, even when you have no symptoms.
2. Laser Treatment
Different types of laser treatment can help fluid drain from your eye:
- Laser Trabeculoplasty: Opens the drainage channels for open-angle glaucoma
- Laser Iridotomy: Creates a tiny hole in the iris to improve fluid flow in angle-closure glaucoma
- Cyclophotocoagulation: Reduces fluid production
3. Surgery
If medication and laser treatment haven't been effective, surgery may be necessary:
-
Minimally Invasive Glaucoma Surgery (MIGS):
Smaller incisions, fewer complications, and faster recovery than traditional surgery
-
Trabeculectomy:
Creates a new drainage pathway for fluid to leave the eye
-
Drainage Implants:
Small devices are placed in the eye to help drain fluid
For details on specific surgeries, please see our surgical guides for
iStent,
Preserflo Microshunt, and
Trabeculectomy and Tube Surgery.
Living with Glaucoma
Living with glaucoma requires some adjustments, but most people maintain good vision throughout their lives:
-
Take medications as prescribed:
Be diligent about using your eye drops exactly as directed.
-
Attend all follow-up appointments:
Regular monitoring is essential to ensure your treatment is working.
-
Protect your eyes:
Wear eye protection during activities that could injure your eyes.
-
Maintain a healthy lifestyle:
Exercise regularly, eat a balanced diet, don't smoke, and maintain a healthy weight.
-
Manage other health conditions:
Keep conditions like diabetes and high blood pressure under control.
Common Myths About Glaucoma
Myth: "Glaucoma only affects older people."
Fact: While glaucoma is more common in older adults, it can affect people of all ages,
even newborns and young adults.
Myth: "If I don't have symptoms, I don't have glaucoma."
Fact: The most common type of glaucoma has no symptoms in its early stages. By the time
you notice vision changes, the disease may be quite advanced.
Myth: "Reading in poor light damages your eyes and can cause glaucoma."
Fact: Reading in poor light does not cause glaucoma or permanently damage your eyes,
although it can cause temporary eyestrain.
Myth: "Glaucoma can be cured."
Fact: At present, there is no cure for glaucoma. However, with proper treatment and
regular monitoring, most people with glaucoma maintain their vision.
Myth: "You can feel if your eye pressure is high."
Fact: Most people cannot feel high eye pressure. That's why regular comprehensive
eye exams are important for detecting glaucoma before damage occurs.
