Types of Glaucoma
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Types of Glaucoma

Glaucoma is not a single disease, but actually a general term that includes multiple subcategories of eye problems. The common feature of these eye disorders grouped under the category of glaucoma is either a high eye pressure, a problem with the drain, or damage to the nerve inside the eye. Strictly speaking, the term glaucoma should only be used when true optic nerve injury has occurred.

Open angle versus narrow or closed angle glaucoma
Fluid is constantly moving through the eye. This fluid, known as the aqueous, provides nutrition to the internal eye structures, and also maintains the round shape to the eyeball to help it function as an amazing optical device. There is a pressure to the aqueous that helps maintain this round shape, much like your car tire has pressure in the air to keep it round. The fluid is produced in one part of the eye (ciliary body) and drains in another area (trabecular meshwork). Normally, the pathway to the drain is widely open so fluid can easily get to the drain – this is known as an open angle. In some people the anatomy of the eye is different. The eye is a little bit smaller which causes less space for the drain, which leads to a narrow angle. As the lens in the eye grows with age the angle becomes narrower until the iris pushes against the drain and leads to a closed angle. With a closed angle the eye pressure increases dramatically which can lead to loss of vision. A narrow angle should be treated with a laser (peripheral iridotomy) to prevent angle closure. People who have narrow angles should avoid medications like cough and cold remedies unless their ophthalmologist says it is safe for their use.

Primary versus secondary glaucoma
Primary Open-angle glaucoma is the most common form of glaucoma. In this eye condition the pathway to the drain is open and fluid can get to the drain, but the actual function of the drain is decreased. The drain is clogged which slows down the flow of the aqueous away from the eye. When this occurs the pressure inside the eye increases. Over time the increased eye pressure pushes against the nerve and leads to nerve injury. Nerve injury when advanced can lead to vision loss. There are many theories about why the drain function decreases in some people leading to glaucoma. Genetics probably plays a major role in determining who will get open-angle glaucoma. Secondary glaucoma develops when other eye conditions lead to drain failure. Examples of secondary glaucoma include injury or trauma, Pigmentary glaucoma, or inflammatory glaucoma.

There are many types of glaucoma that affect people in all age groups. The most important aspect of glaucoma care is preventing ongoing nerve injury to save vision.