What is Glaucoma?
Glaucoma is an umbrella term that refers to a series of eye conditions that cause permanent damage to the optic nerve, which is the communication pathway between your eyes and brain.
Glaucoma is caused by fluid build-up in the front of the eye, leading to increased eye pressure on the optic nerve. This high pressure is also called ocular hypertension. If left untreated, it will cause irreversible damage and eventually blindness.
Early treatment can prevent vision changes and blindness. However, there is not a cure for glaucoma. If you are diagnosed with the condition, you will likely need to follow a treatment plan for the rest of your life.
There are five different types of glaucoma. They are categorized based on the underlying cause.
5 Types of Glaucoma and Their Symptoms
The front of your eyes produces a constant flow of clear liquid (aqueous humor) to help keep them nourished and healthy. This liquid is also responsible for eye shape and normal intraocular pressure (IOP).
The liquid must drain out of the eye at the same rate it comes in to maintain a constant pressure. It does this through the drainage angle. If the balance is off even slightly, IOP can increase, causing glaucoma and permanent damage to the optic nerve.
The most common types of glaucoma stem from problems with the drainage angle. Other types of glaucoma can result from a different health condition or injury that causes the IOP to increase.
1. Acute Angle-Closure Glaucoma
Acute angle-closure glaucoma is a less common type of glaucoma. It is caused by the iris (controls how much light comes in) slipping into a position that blocks the drainage angle. This blockage results in your eye pressure increasing rapidly, causing an acute attack.
Acute angle-closure glaucoma is a medical eye emergency that needs to be treated by an ophthalmologist immediately before permanent vision loss or blindness occurs.
Acute angle-closure glaucoma is considered acute because the IOP rises faster.
Warning signs are usually noticeable right away and include:
- Hazy or blurred vision
- Severe pain in the eye or forehead
- Eye redness
- Rainbows or halos
If you have any of these symptoms, seek medical treatment right away. A delay in treatment could result in blindness.
Since acute angle-closure glaucoma is a medical emergency, the first line of treatment will include steps to decrease eye pressure.
After the pressure stabilizes, you will need to visit an ophthalmologist immediately. They may recommend laser or conventional surgery to create a channel in which fluid can exit the eye. Eye doctors will typically prescribe daily eye drops and other medication to keep the IOP within a normal range.
2. Open-Angle Glaucoma
Open-angle glaucoma is the most common type of glaucoma. Open-angle means that access to the drainage angle is open. The drainage angle is where the eye's iris meets the cornea (the clear covering on the front of the eye allows light to go in).
Open-angle glaucoma is often associated with a gradual progression of increased IOP caused by a slowing drainage rate, similar to a clogged drain.
Since it happens over time, there is typically no pain or symptoms to warn you of the increased IOP and damage to the optic nerve. The absence of symptoms can lead to a late diagnosis when vision loss has already started.
The first warning signs of open-angle glaucoma are typically blind spots in your peripheral vision (side vision). Other symptoms may include:
- Use of stairs become difficult
- Eye ache
- Cloudy vision
Treatment for open-angle glaucoma typically includes a combination of medication and either laser or glaucoma surgery.
Treatment options include:
- Daily eye drops to help decrease the intraocular pressure
- Medications like beta-blockers, alpha agonists, carbonic anhydrase inhibitors, or miotics
- Laser surgery, such as trabeculoplasty or iridotomy
- Traditional surgery, such as trabeculectomy, glaucoma drainage device, or cataract surgery
3. Secondary Glaucoma
Secondary glaucoma occurs due to a secondary medical issue that causes the increase in eye pressure, such as:
- Eye injury
- Certain medications
Secondary glaucoma can be either the open-angle or angle-closure type of glaucoma and may occur in one or both eyes.
Common types of secondary glaucoma include:
- Steroid-induced glaucoma from the use of steroid eye drops or systemic steroids
- Trauma-induced glaucoma, typically caused by blunt force trauma
- Uveitic glaucoma, which causes inflammation in the middle layer of the eye
- Neovascular glaucoma, which is when newly formed blood vessels cover the drainage angle. It’s typically associated with diabetes.
- Exfoliative glaucoma, which is caused by a flaky material falling off the eye lens, clogging the drainage angle.
Pigmentary glaucoma is another common type of secondary glaucoma. It develops from pigment dispersion syndrome when pigment material breaks free and clogs your drainage angle. Pigment material gives your eye color and is located on your iris.
Pigmentary glaucoma is rare and often caused by vigorous physical activity such as jogging or basketball in people with pigment dispersion syndrome.
Depending on the underlying cause of secondary glaucoma, there may not be any signs or symptoms until changes in vision are noticed.
Like open-angle glaucoma, symptoms usually begin with blind spots in peripheral vision.
Treatment for this type of glaucoma will include first treating the root cause of the IOP increase. If the problem persists, medication and surgery may normalize the intraocular pressure.
4. Normal-Tension Glaucoma
Normal-tension glaucoma, also called low-tension glaucoma and normal-pressure glaucoma is damage to the optic nerve not caused by increased eye pressure.
People diagnosed with this type of glaucoma have normal eye pressure. It is currently considered a form of open-angle glaucoma.
Because normal-tension glaucoma is a type of open-angle glaucoma, there usually are not any signs or symptoms until the optic nerve damage progresses into vision loss.
Normal-tension glaucoma is treated with a combination of medication and a form of either laser or traditional surgery.
5. Glaucoma in Children
Congenital glaucoma, also called childhood glaucoma, occurs when a baby’s drainage canal does not develop properly in-vitro. It is typically diagnosed within the first year of life and is often hereditary. It is a rare condition.
Symptoms of congenital glaucoma typically include:
- Enlarged eyes
- Excessive tearing
- Sensitivity to light
Surgery and medication are the gold standards to treat this type of glaucoma. Many babies with childhood glaucoma go on to live full lives.
What are the Risk Factors for Glaucoma?
While people of any age can get glaucoma, those over 60 are at a much higher risk. People can have glaucoma in one or both eyes.
Family history and environmental risk factors also play a significant role in glaucoma development.
These risk factors include:
- Another family member with glaucoma
- African American, Asian, and Hispanic populations
- History of steroid use
- Eye injury
- Severe myopia (nearsightedness)
- Hypertension (high blood pressure)
- Thinner cornea (less than .5 mm)
Diagnosing and Treating Glaucoma
Early detection is critical for stopping glaucoma. Diagnosis is made during a comprehensive eye exam by a licensed eye doctor.
The cause and type of glaucoma will determine glaucoma treatment. The initial goal of treating glaucoma is to get the intraocular pressure down to a normal level. This is typically done through daily eye drops and other forms of medication, including:
- Alpha agonists
- Carbonic anhydrase inhibitors
Laser surgery and traditional surgery are commonly used to correct the problem with the drainage angle.
These surgeries may include:
- Trabeculoplasty. Improves the function of the drainage angle for better fluid flow.
- Iridotomy. A small hole is created in the iris to help with fluid drainage.
- Trabeculectomy. Creates a new drainage channel.
- Glaucoma drainage device. Implantation of a tiny drainage tube.
- Cataract surgery. Removal of the natural lens to reduce eye pressure.
Can You Prevent Glaucoma?
Glaucoma is a severe disease, but with routine eye exams, it can be prevented.
Knowing your risk factors and the signs and symptoms can help stop the progress of glaucoma before vision loss occurs.
Glaucoma, also called the "sneak thief of sight," is particularly dangerous. It often doesn't have any symptoms or warning signs until the advanced stage of the disease. For this reason, it is crucial to get routine eye exams from an optometrist or ophthalmologist.
There are five different types of glaucoma, and they are typically categorized in either the open-angle or angle-closure kind of glaucoma, depending on the fluid drainage issue. The leading cause of glaucoma is an increase in intraocular pressure that damages the optic nerve.
The gold standard of treating glaucoma is a combination of medication and either laser or traditional eye surgery to allow fluid to flow evenly and decrease intraocular pressure.
Acute angle-closure glaucoma is a medical emergency and should be treated immediately before permanent sight loss occurs.
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