Doctor's Notes on Primary Open-Angle Glaucoma (POAG)
Primary open-angle glaucoma (POAG) is the most common type of glaucoma. It is one of the leading preventable causes of blindness in the world, and it is the most common cause of blindness in African-Americans. In POAG, there is the characteristic optic nerve damage associated with open angles (the area between the iris and cornea) and elevated eye pressure. This is different from other types of glaucoma, which are associated with abnormal angles (for example, narrow-angle glaucoma, closed-angle glaucoma, primary congenital glaucoma, and other secondary glaucomas) or low eye pressures (normal tension glaucoma).
In the early stages, primary open-angle glaucoma may cause no symptoms. The main signs of primary open-angle glaucoma are
- the presence of a thinned (atrophied) optic nerve and the presence of an open angle,
- both of which can be seen using specialized instruments during an eye examination.
By the time symptoms of vision loss or blind spots in primary open-angle glaucoma occur the disease is usually in the later stages and irreversible optic nerve damage may have already occurred.
What Is the Treatment for Primary Open-Angle Glaucoma?
Primary open-angle glaucoma is treated with medications or surgery. Medications prescribed for open-angle glaucoma are designed to either increase the outflow of fluids in the eye or decrease the overall production of fluids in the eye in order to keep intraocular pressure under control. Drug combinations are often used to control intraocular pressure because they have a greater benefit than any single drug used by itself. Common drug classes used to treat open-angle glaucoma include:
- Prostaglandins
- Latanoprost
- Bimatoprost
- Tafluprost
- Alpha adrenergic agonists
- Brimonidine
- Epinephrine
- Cholinergic agonists
- Rho kinase inhibitors
- Netarsudil
- Beta blockers
- Carbonic anhydrase inhibitors
- Dorzolamide
- Combination products are available for several classes of drugs including most commonly:
- Latanoprost-timolol
- Travoprost-timolol
- Dorzolamide-timolol
- Brimonidine-timolol
- Netarsudil-latanoprost
Some cases require a surgical procedure to keep intraocular pressure under control. Common glaucoma treatment procedures include
- Laser therapy (trabeculoplasty)
- Argon laser trabeculoplasty
- Surgical therapy (trabeculectomy) with creation of a filtration bleb
- Placement of mechanical shunts
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Adult Glaucoma Suspect
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Angle Recession Glaucoma
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Glaucoma
Glaucoma can be caused by a number of eye diseases that can damage the optic nerve, typically by elevating pressure inside the eye, which is called intraocular pressure (IOP) or ocular hypertension. Symptoms begin slowly and include vision loss and irregularities, eye pain, headache, nausea, and vomiting. Beta-blockers, Alpha-adrenergic agonists, and prostaglandin analogs are drugs used to treat glaucoma. Sometimes surgery is necessary, especially with congenital glaucoma. The disease is not curable but can be managed. -
Glaucoma FAQs
Glaucoma is usually high pressure inside the eye that damages the optic nerve and can result in permanent vision loss. While high pressure inside the eye, damage to the optic nerve and vision loss are common criteria for diagnosing glaucoma, glaucoma can be present without all three of these criteria. The two main types of glaucoma are open-angle and angle-closure glaucoma. Glaucoma may be symptomless until significant permanent vision damage has occured, but may show symptoms as well, including pain, redness, haloes, and blurred vision. -
Glaucoma Medications
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Lens-Particle Glaucoma
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Normal-Tension Glaucoma
Normal-tension glaucoma or low-tension glaucoma is a condition in which the optic nerve is damaged despite normal fluid pressure inside the eye (other types of glaucoma result vision loss because of abnormally high pressure inside the eye. Normal-tension glaucoma typically occurs in older adults and can be caused by congenital nerve defects and irregularities in blood flow to the eye. Eyedrops and surgery are treatments for this disorder. -
Ocular Hypertension
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Primary Congenital Glaucoma
Primary congenital glaucoma is present at birth and may be inherited. Blepharospasm, photophobia, and epiphora are symptoms. A cloudy whitish-gray cornea is a common sign. Treatment of primary congenital glaucoma typically involves surgery. -
What Is Usually the First Sign of Glaucoma?
Early glaucoma usually has few symptoms, but the buildup of pressure in the eye over time leads to slow vision loss starting with peripheral vision.
REFERENCE:
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.