Glaucoma is a progressive, irreversible eye disease that causes vision loss due to optic nerve damage.
The eye is filled with a fluid called ‘aqueous humor’, responsible for nourishing the lens and other important structures in the eye. The pressure exerted by the fluid inside your eye is called intraocular pressure, or IOP.
The aqueous humor is constantly produced and drained at a balanced rate to ensure the health of the lens and cornea. When this drainage becomes blocked, or there is an increase in fluid production, IOP increases and glaucoma occurs. Over time, this increase in IOP can cause damage to some of the sensitive structures that receive and transmit images in the eye, including the optic nerve. The pressure damage of glaucoma causes a gradual blurring of vision and, if left untreated, can result in total, irreversible blindness.
Initially, someone suffering from glaucoma may notice a gradual loss of peripheral (side) vision, before progressing to a complete loss of peripheral vision so that only a small area of central vision remains. Because there are no symptoms associated with the disease in its early stages, regular eye examinations with your ophthalmologist or optometrist are important.
Normal Vision
Advanced Glaucoma
Types of Glaucoma
There are two main types of glaucoma: open-angle glaucoma and angle-closure glaucoma.
Open-Angle Glaucoma
The most common type of glaucoma, open-angle glaucoma, accounts for approximately 70% to 90% of all cases. The disease is progressive and has no detectable early signs. Elevated IOP is the most significant risk factor for the development and progression of open-angle glaucoma.
As eye pressure builds, it gradually can lead to:
- Damage of the optic nerve
- Loss of peripheral vision
- Blindness, if left untreated
Angle-Closure Glaucoma
The second most common type of glaucoma — angle-closure glaucoma — occurs when the drainage pathways in the eye become blocked by the iris. As a result, fluid cannot circulate through the eye and pressure increases. The condition can occur suddenly (acute angle-closure glaucoma) or gradually (chronic angle-closure glaucoma).
Your eye care professional can perform a simple eye test to determine if the angle in your eye is normal and wide or abnormal and narrow.
SYMPTOMS
Open-angle glaucoma has no obvious symptoms in its early stage. As the disease progresses, blind spots can begin to develop in the peripheral (side) view. These spots can go undetected until the optic nerve has experienced serious damage, or until detected by an eye care specialist through a complete eye exam.
Similarly, people at risk for angle-closure glaucoma often do not experience symptoms before it occurs. Symptoms of angle-closure glaucoma may include
- Severe pain in the eyes or forehead
- Redness of the eye
- Decreased vision or blurred vision
- Seeing halos around lights
Scheduling a comprehensive dilated eye exam at least once a year with an eye care professional is crucial in finding out whether you have glaucoma, since people who are diagnosed with the disease often do not experience glaucoma symptoms, or are even aware they have the condition.
RISK FACTORS
Many risk factors exist for the development of glaucoma. Some of these include:
- Elevated eye pressure
- Sudden considerable changes in eye pressure
- Over age 60
- Family history of glaucoma
- Decreased central corneal thickness (less than 0.5 mm)
- Blunt eye trauma
- Inflammatory eye conditions
If you have one or more of the glaucoma risk factors listed you should visit your eye care professional for a full glaucoma exam. Early detection and treatment of high eye pressure is your best defense against glaucoma.