There are quite a few different types of glaucoma, with two of the most common being open-angle glaucoma and closed-angle glaucoma. Whether you have been diagnosed with glaucoma or not, it is useful to have a basic understanding of the two in case you experience any symptoms.
In this post, the team at Boston Eye Physicians and Surgeons breaks down the differences between the two types of glaucoma.
The Drainage Angle
The “angle” is short for the drainage angle, or the area where the eye’s iris meets the cornea. The cornea is the transparent covering of the eye, and the iris is the colored part of the eye.
Fluid is consistently produced inside the eye and leaves the front of the eye through the drainage angle. The drainage angle contains sponge-like tissue known as the trabecular meshwork. Most of the fluid exiting the eye drains through this tissue and makes its way into the body’s circulatory system.
The status of the drainage angle dictates the specific type of glaucoma.
Open-angle glaucoma develops when the drainage angle is technically wide and open but fluid drains slower than normal through the trabecular meshwork. An imbalance between the amount of fluid produced in the eye and the amount of fluid that leaves the eye causes fluid accumulation and in turn, a slow rise in intraocular pressure.
Closed-angle glaucoma (also known as angle-closure, acute or narrow-angle glaucoma) develops when the drainage angle narrows or closes. This happens when the iris bulges forward. Unlike open-angle glaucoma, fluid accumulates very quickly in the front of the eye and intraocular pressure spikes dangerously in closed-angle glaucoma.
Symptoms
Because open-angle glaucoma occurs slowly over time, symptoms are typically not very noticeable. It may take years to detect a change in vision, with peripheral vision being the first to deteriorate.
On the other hand, closed-angle glaucoma causes impossible-to-ignore symptoms that come on very suddenly: eye pain, headaches, nausea, vomiting and blurry or unfocused vision are common. Closed-angle glaucoma is a medical emergency; should you experience any of the warning signs, go to the closest emergency room or call your eye doctor immediately.
Treatment Options
Because the two types of glaucoma differ in severity, the treatment protocols also differ.
Many patients with open-angle glaucoma opt to start with an eye drop protocol to lower intraocular pressure. Eye drops either slow down the formation of fluid inside the eye or improve the way fluid drains out of the eye. Patients who either do not want to use eye drops or cannot tolerate the drops may undergo a laser procedure called selective laser trabeculoplasty, which treats the trabecular meshwork tissue to improve the way fluid exits the eye. If drops or laser treatment fail to produce the desired improvements in intraocular pressure, traditional surgical treatment may be considered.
Cases of closed-angle glaucoma require immediate intervention to repair the bunched-up iris. Laser or traditional surgery is usually performed to smooth out the iris and open up the drainage angle so fluid can drain properly from the eye.
Contact Us Today
If you have further questions about glaucoma, the doctors at Boston Eye Physicians and Surgeons invite you to call or email us today.
