Glaucoma
What Is Glaucoma?
Glaucoma is a group of eye diseases that damage the optic nerve, the structure responsible for transmitting visual information from the eye to the brain. This damage is often associated with elevated intraocular pressure (IOP), although glaucoma can also occur in individuals with normal eye pressure. Left untreated, glaucoma can lead to progressive and irreversible vision loss.
Often referred to as the “silent thief of sight,” the most common form of glaucoma develops gradually and typically causes no noticeable symptoms in its early stages. Because vision loss from glaucoma is permanent and usually begins with peripheral (side) vision, many people are unaware they have the condition until significant damage has already occurred.
Regular comprehensive eye examinations are essential for early detection. When diagnosed early, glaucoma can often be monitored and managed to help preserve vision.
Types of Glaucoma
01
Primary Open-Angle Glaucoma
Primary open-angle glaucoma is the most common type of glaucoma. It develops gradually when the eye’s drainage system becomes less efficient, leading to progressive damage of the optic nerve. Most patients experience no pain or early symptoms, making routine eye examinations especially important.
02
Angle-Closure Glaucoma
Angle-closure glaucoma occurs when the drainage angle between the iris and cornea becomes partially or completely blocked, causing eye pressure to rise rapidly. Acute angle-closure glaucoma is a medical emergency and requires immediate treatment to prevent permanent vision loss.
03
Normal-Tension Glaucoma
Some individuals develop glaucoma even though their intraocular pressure remains within the normal range. The exact cause is not fully understood, but factors such as reduced blood flow to the optic nerve and increased susceptibility of the nerve may contribute.
04
Secondary Glaucoma
Secondary glaucoma develops as a result of another eye condition or systemic factor, such as eye trauma, inflammation (uveitis), prolonged corticosteroid use, pigment dispersion, pseudoexfoliation syndrome, or certain eye surgeries.
05
Congenital Glaucoma
Congenital glaucoma is a rare condition present at birth or early childhood due to abnormal development of the eye’s drainage system. Early diagnosis is important to preserve vision.
Symptoms of Glaucoma
Symptoms depend on the type and stage of glaucoma.
Primary Open-Angle Glaucoma
In its early stages, primary open-angle glaucoma usually causes no symptoms. As the disease progresses, symptoms may include:
- Gradual loss of peripheral (side) vision
- Difficulty seeing objects to the side
- Tunnel vision in advanced stages
Because central vision is often preserved until late in the disease, many patients remain unaware of vision loss without formal testing.
Acute Angle-Closure Glaucoma
Acute angle-closure glaucoma develops suddenly and is considered an ophthalmic emergency.
Symptoms may include:
- Severe eye pain
- Sudden blurred vision
- Red eye
- Headache
- Halos around lights
- Nausea or vomiting
Anyone experiencing these symptoms should seek immediate ophthalmic evaluation.
What Causes Glaucoma?
Glaucoma develops when damage occurs to the optic nerve. Elevated intraocular pressure is one of the most significant risk factors, but it is not the only cause. Some individuals with high eye pressure never develop glaucoma, while others develop optic nerve damage despite having pressures within the normal range.
Damage may result from:
- Impaired drainage of aqueous humor
- Elevated intraocular pressure
- Reduced blood flow to the optic nerve
- Structural susceptibility of the optic nerve
- Certain inherited genetic factors
Because glaucoma is a complex disease, each patient’s condition is unique.
Risk Factors
Several factors increase the likelihood of developing glaucoma, including:
- Age over 60
- Family history of glaucoma
- Elevated intraocular pressure
- African American, Hispanic/Latino, or Asian ancestry (depending on glaucoma subtype)
- Diabetes
- High myopia (nearsightedness)
- Thin central corneas
- Previous eye injury
- Long-term corticosteroid use
- Certain vascular conditions
Having one or more risk factors does not necessarily mean you will develop glaucoma, but regular eye examinations become increasingly important.
How Are Glaucoma Diagnosed?
A comprehensive glaucoma evaluation includes much more than measuring eye pressure.
Your ophthalmologist may perform:
- Measurement of intraocular pressure (tonometry)
- Examination of the optic nerve
- Dilated eye examination
- Gonioscopy to evaluate the drainage angle
- Optical Coherence Tomography (OCT) of the optic nerve and retinal nerve fiber layer
- Visual field testing (perimetry)
- Pachymetry to measure central corneal thickness
These tests help determine whether glaucoma is present, assess disease severity, and establish a baseline for future monitoring.
Can Glaucoma Be Prevented?
There is currently no proven way to prevent glaucoma. However, early detection remains the most effective way to reduce the risk of vision loss.
Routine comprehensive eye examinations are particularly important for individuals with risk factors or a family history of glaucoma.
Maintaining overall cardiovascular health, managing chronic medical conditions, and attending regular follow-up appointments can also support long-term eye health.
When Should You See an Ophthalmologist?
Schedule a comprehensive eye examination if you:
- Have a family history of glaucoma
- Are over the age of 60
- Have elevated eye pressure
- Have diabetes or significant nearsightedness
- Notice changes in your peripheral vision
- Experience sudden eye pain, blurred vision, halos around lights, nausea, or vomiting
Because glaucoma often develops without early warning signs, regular eye examinations remain the best way to detect the disease before permanent vision loss occurs.
Frequently Asked Questions
No. While elevated intraocular pressure is a major risk factor, glaucoma can occur even when eye pressure falls within the normal range. This is known as normal-tension glaucoma.
Currently, glaucoma cannot be cured, and vision already lost cannot be restored. However, with early diagnosis and appropriate management, progression can often be slowed or stabilized.
No. The most common form, primary open-angle glaucoma, usually develops without noticeable symptoms until significant vision loss has occurred.
No. Elevated eye pressure alone does not mean glaucoma is present. Some people have ocular hypertension without optic nerve damage, while others develop glaucoma despite normal eye pressure.
The American Academy of Ophthalmology recommends comprehensive eye examinations at intervals based on age, risk factors, and overall eye health. Individuals with a family history of glaucoma or other risk factors may require more frequent evaluations.
