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A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M.; 2013.

A.D.A.M. Medical Encyclopedia.

Glaucoma

Open-angle glaucoma; Chronic glaucoma; Chronic open-angle glaucoma; Primary open-angle glaucoma; Closed-angle glaucoma; Narrow-angle glaucoma; Angle-closure glaucoma; Acute glaucoma; Secondary glaucoma; Congenital glaucoma

Last reviewed: August 24, 2013.

Glaucoma

 

Glaucoma is a group of eye conditions that can damage the optic nerve. This nerve sends the images you see to your brain.

Most often, optic nerve damage is caused by increased pressure in the eye. This is called intraocular pressure.

Causes, incidence, and risk factors

Glaucoma is the second most common cause of blindness in the U.S. There are four major types of glaucoma:

  • Open-angle glaucoma
  • Angle-closure glaucoma, also called closed-angle glaucoma
  • Congenital glaucoma
  • Secondary glaucoma

The front part of the eye is filled with a clear fluid called aqueous humor. This fluid is made in an area behind the colored part of the eye (iris). It leaves the eye through channels where the iris and cornea meet. This area is called the anterior chamber angle, or the angle. The cornea is the clear covering on the front of the eye that covers the iris, pupil, and angle.

Anything that slows or blocks the flow of this fluid will cause pressure to build up in the eye.

  • In open-angle glaucoma, the increase in pressure is often small and slow.
  • In closed-angle, the increase is often high and sudden.
  • Either type can damage the optic nerve.

Open-angle glaucoma is the most common type of glaucoma.

  • The cause is unknown. The increase in eye pressure happens slowly over time. You can't feel it.
  • The increased pressure pushes on the optic nerve. Damage to the optic nerve causes blind spots in your vision.
  • Open-angle glaucoma tends to run in families. Your risk is higher if you have a parent or grandparent with open-angle glaucoma. People of African descent are also at higher risk for this disease.

Closed-angle glaucoma occurs when the fluid is suddenly blocked and can't flow out of the eye. This causes a quick, severe rise in eye pressure.

  • The sudden increase in pressure causes eye pain.
  • Closed-angle glaucoma is an emergency.
  • If you have had acute glaucoma in one eye, you are at risk for it in the second eye. Your doctor is likely to treat your second eye to try prevent another attack.

Secondary glaucoma occurs due to a known cause. Both open- and closed-angle glaucoma can be secondary when caused by something known. Causes include:

  • Drugs such as corticosteroids
  • Eye drops that dilate your eyes
  • Eye diseases such as uveitis (an infection of the middle layer of the eye)
  • Diseases such as diabetes
  • Eye injury

Congenital glaucoma occurs in babies.

  • It often runs in families.
  • It is present at birth.
  • It is caused when the eye does not develop normally.

Symptoms

OPEN-ANGLE GLAUCOMA

  • Most people have no symptoms
  • Once vision loss occurs, the damage is already severe
  • Slow loss of side (peripheral) vision (also called tunnel vision)
  • Advanced glaucoma can lead to blindness

ANGLE-CLOSURE GLAUCOMA

Symptoms may come and go at first, or steadily become worse. You may notice:

  • Sudden, severe pain in one eye
  • Decreased or cloudy vision, often called "steamy" vision
  • Nausea and vomiting
  • Rainbow-like halos around lights
  • Red eye
  • Eye feels swollen

CONGENITAL GLAUCOMA

Symptoms are usually noticed when the child is a few months old.

  • Cloudiness of the front of the eye
  • Enlargement of one eye or both eyes
  • Red eye
  • Tearing

SECONDARY GLAUCOMA

  • Symptoms are usually related to the underlying problem causing the glaucoma
  • Depending on the cause, symptoms may either be like open-angle glaucoma or angle-closure glaucoma

Signs and tests

The only way to diagnose glaucoma is by having a complete eye exam.

  • Usually you'll be given eye drops to widen (dilate) your pupil.
  • When your pupil is dilated, your eye doctor will look at the inside of your eye and the optic nerve.
  • You may be given a test to check your eye pressure. This is called tonometry.
Slit-lamp exam

Eye pressure is different at different times of the day. Eye pressure can even be normal in some people with glaucoma. So your doctor will need to run other tests to confirm glaucoma. They may include:

  • Using a special lens to look at the angle of the eye (gonioscopy)
  • Photographs or laser scanning images of the inside of your eye (optic nerve imaging)
  • Checking your retina. The retina is the light sensitive tissue at the back of your eye.
  • Checking how your pupil responds to light (pupillary reflex response)
  • 3-D view of your eye (slit lamp examination)
  • Testing the clearness of your vision (visual acuity)
  • Testing your field of vision (visual field measurement)
Visual field test

Treatment

The goal of treatment is to reduce your eye pressure. Treatment depends on the type of glaucoma that you have.

OPEN-ANGLE GLAUCOMA

  • If you have open-angle glaucoma, you will probably be given eye drops.
  • You may need more than one type. Most people can be treated with eye drops.
  • Most of the eye drops used today have fewer side effects than those used in the past.
  • You also may be given pills to lower pressure in the eye.

If drops alone don't work, you may need other treatment:

  • Laser treatment uses a painless laser to open the channels where fluid flows out.
  • If drops and laser treatment don't work, you may need surgery. You will be put asleep with general anesthesia. The doctor will use a small knife to cut open a new channel so fluid can escape. This will help lower your pressure.

ACUTE ANGLE GLAUCOMA

An acute angle-closure attack is a medical emergency. You can become blind in a few days if you aren't treated.

  • You may be given drops, pills, and medicine given through a vein (by IV) to lower your eye pressure.
  • Some people also need an emergency operation, called an iridotomy. The doctor uses a laser to open a new channel in the iris. Sometimes this is done with surgery. The new channel relieves the attack and will prevent another attack.
  • To help prevent an attack in the other eye, the procedure will often be performed on the other eye. This may be done even if it has never had an attack.

CONGENTIAL GLAUCOMA

  • Congenital glaucoma is almost always treated with surgery.
  • This is done using general anesthesia. This means the child is asleep and feels no pain.

SECONDARY GLAUCOMA

If you have secondary glaucoma, treating the cause may help your symptoms go away. Other treatments also may be needed.

Expectations (prognosis)

Open-angle glaucoma can't be cured. You can manage it and keep your sight by following your doctor's directions.

Closed-angle glaucoma is a medical emergency. You need treatment right away to save your vision.

Babies with congenital glaucoma usually do well when surgery is done early.

How you do with secondary glaucoma depends on what is causing the condition.

Calling your health care provider

If you have severe eye pain or a sudden loss of vision, get immediate medical help. These may be signs of closed-angle glaucoma.

Prevention

You can't prevent open-angle glaucoma. Most people have no symptoms. But you can help prevent vision loss.

  • A complete eye exam can help find open-angle glaucoma early, when it is easier to treat.
  • All adults should have a complete eye exam by the age of 40.
  • If you are at risk for glaucoma, you should have a complete eye exam sooner than age 40.
  • You should have regular eye exams as recommended by your doctor.

If you are at risk for closed-angle glaucoma, your doctor may recommend treatment before you have an attack to help prevent eye damage and vision loss.

References

  1. Anderson DR. The Optic Nerve in Glaucoma. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2013:vol 3, chap 48.
  2. Kwon YK, Caprioli J. Primary Open-Angle Glaucoma. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2013:vol 3, chap 52.
  3. Giaconi JA, Law SK, Caprioli J. Primary Angle-Closure Glaucoma. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2013:vol 3, chap 53.
  4. Mandelcorn E, Gupta N. Lens-Related Glaucomas. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2013:vol 3, chap 54A.

Review Date: 8/24/2013.

Reviewed by: Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.

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The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

What works?

  • Comparison of two surgical techniques for the control of eye pressure in people with glaucoma
    Increased eye pressure is the major risk factor for developing glaucoma (a group of eye diseases that lead to progressive, irreversible damage to the optic nerve (the nerve that transmits visual information from the retina to the brain)). Glaucoma is the second biggest cause of blindness worldwide. Eye pressure can be controlled surgically. Trabeculectomy (penetrating eye surgery) is the removal of a full‐thickness block of the trabecular meshwork (eye filtration tissue) to make a hole that allows aqueous (watery fluid present in the front part of the eyes and partly responsible for eye pressure) to filter out of the eye. It is the standard surgical procedure and has been widely practised for over 40 years. Non‐penetrating filtering surgical procedures, in which aqueous is allowed to filter out without the removal of a full‐thickness block of trabecular tissue, also aim to control eye pressure and have the reputation of being safer than trabeculectomy. The most widely practised non‐penetrating surgical procedures for glaucoma are viscocanalostomy and deep sclerectomy. Each procedure involves a different level of partial‐thickness surgical dissection into the eye filtration tissue. Surgical success is defined as lowering the eye pressure to normal limits (less than 21 mmHg) for at least 12 months after surgery. This review included five trials with 311 eyes (267 participants). These studies included 160 eyes which had trabeculectomy compared to 151 eyes that had non‐penetrating glaucoma surgery, of which 101 eyes had deep sclerectomy and 50 eyes had viscocanalostomy. This review showed that trabeculectomy is better in terms of achieving total success (pressure controlled without eyedrops) than non‐penetrating filtering procedures. Although when we looked at the outcome of partial success (pressure controlled with additional eyedrops) it was more imprecise and our results could not exclude one surgical approach being better than the other. However, the review noted that these studies had some limitations regarding their design and were too small to give definitive information on differences in complications following surgery. None of the studies measured quality of life.
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    Slit-lamp exam.
    Visual field test.
    Glaucoma.

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