Glaucoma

Glaucoma is a group of eye conditions that damage the optic nerve, causing vision loss and even blindness. The optic nerve sends visual information from your eye to your brain and is vital for good vision. Damage to the optic nerve is often related to high pressure in your eye. But glaucoma can happen even with normal eye pressure.

Glaucoma can occur at any age but is more common in older adults. It is one of the leading causes of blindness for people over the age of 60.

Many forms of glaucoma have no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is in its later stages.

It's important to have regular eye exams that include measurements of your eye pressure. If glaucoma is recognized early, vision loss can be slowed or prevented. If you have glaucoma, you'll need treatment or monitoring for the rest of your life.

## Symptoms

The symptoms of glaucoma depend on the type and stage of your condition.

Open-angle glaucoma:

* No symptoms in early stages
* Gradually, patchy blind spots in your side vision. Side vision also is known as peripheral vision
* In later stages, difficulty seeing things in your central vision

Acute angle-closure glaucoma:

* Severe headache
* Severe eye pain
* Nausea or vomiting
* Blurred vision
* Halos or colored rings around lights
* Eye redness

Normal-tension glaucoma:

* No symptoms in early stages
* Gradually, blurred vision
* In later stages, loss of side vision

Glaucoma in children:

* A dull or cloudy eye (infants)
* Increased blinking (infants)
* Tears without crying (infants)
* Blurred vision
* Nearsightedness that gets worse
* Headache

Pigmentary glaucoma:

* Halos around lights
* Blurred vision with exercise
* Gradual loss of side vision

## Causes

Glaucoma develops when the optic nerve becomes damaged. As this nerve gradually deteriorates, blind spots develop in your vision. For reasons that doctors don't fully understand, this nerve damage is usually related to increased pressure in the eye.
Elevated eye pressure happens as the result of a buildup of fluid that flows throughout the inside of the eye. This fluid also is known as the aqueous humor. It usually drains through a tissue located at the angle where the iris and cornea meet. This tissue also is called the trabecular meshwork. The cornea is important to vision because it lets light into the eye. When the eye makes too much fluid or the drainage system doesn't work properly, eye pressure may increase.

The types of glaucoma include:

* Open-angle glaucoma: This is the most common form of glaucoma. The drainage angle formed by the iris and cornea remains open. But other parts of the drainage system don't drain properly. This may lead to a slow, gradual increase in eye pressure.
* Angle-closure glaucoma: This form of glaucoma occurs when the iris bulges. The bulging iris partially or completely blocks the drainage angle. As a result, fluid can't circulate through the eye and pressure increases. Angle-closure glaucoma may occur suddenly or gradually.
* Normal-tension glaucoma: No one knows the exact reason why the optic nerve becomes damaged when eye pressure is normal. The optic nerve may be sensitive or experience less blood flow. This limited blood flow may be caused by the buildup of fatty deposits in the arteries or other conditions that damage circulation. The buildup of fatty deposits in the arteries also is known as atherosclerosis.
* Glaucoma in children: A child may be born with glaucoma or develop it in the first few years of life. Blocked drainage, injury or an underlying medical condition may cause optic nerve damage.
* Pigmentary glaucoma: In pigmentary glaucoma, small pigment granules flake off from the iris and block or slow fluid drainage from the eye. Activities such as jogging sometimes stir up the pigment granules. That leads to a deposit of pigment granules on tissue located at the angle where the iris and cornea meet. The granule deposits cause an increase in pressure.

Glaucoma tends to run in families. In some people, scientists have identified genes related to high eye pressure and optic nerve damage.

## Risk factors

Glaucoma can damage vision before you notice any symptoms. So be aware of these risk factors:

* High internal eye pressure, also known as intraocular pressure
* Age over 55 and above
* Black, Asian or Hispanic heritage
* Family history of glaucoma
* Certain medical conditions, such as diabetes, migraines, high blood pressure and sickle cell anemia
* Corneas that are thin in the center
* Extreme nearsightedness or farsightedness
* Eye injury or certain types of eye surgery
* Taking corticosteroid medicines, especially eye drops, for a long time
* Some people have narrow drainage angles, putting them at increased risk of angle-closure glaucoma.

## Treatment

Unfortunately, the damage caused by glaucoma currently can't be reversed. But treatment and regular checkups can help slow or prevent vision loss, especially if you catch the disease in its early stages. Glaucoma is treated by lowering intraocular pressure. Treatment options include prescription eye drops, oral medicines, laser treatment, surgery or a combination of approaches.

### Medications

Glaucoma treatment often starts with prescription eye drops. Some may decrease eye pressure by improving how fluid drains from your eye. Others decrease the amount of fluid your eye makes. Depending on how low your eye pressure needs to be, you may be prescribed more than one eye drop.

Eyedrops used to treat glaucoma include prostaglandins, beta blockers, alpha-adrenergic agonists, carbonic anhydrase inhibitors, rho kinase inhibitors, and miotic or cholinergic agents.

Oral medications are also used to treat glaucoma.

### Surgery

Some treatments require surgery. Surgery for glaucoma helps to drain fluid within the eye and lower eye pressure to stop the progression of vision loss. Surgery for glaucoma includes laser therapy, filtering surgery, drainage tubes, and mimimally invasive glaucoma surgery.