What is glaucoma?
There are 2 kinds of glaucoma: Narrow angle (or angle-closure) glaucoma and open angle glaucoma. In narrow angle glaucoma, which is the less common form, there can be acute symptoms such as severe eye pain, decreased vision and redness. This form of glaucoma needs immediate attention. If you have been told that you are predisposed to this form of glaucoma, you should read all medication packaging carefully (including those that are over the counter). Some medications can cause an acute narrow angle closure attack in patients predisposed to this form of glaucoma.
This blog is about open angle glaucoma, the more common of the 2 types.
Open angle glaucoma is a silent, painless eye disease that can permanently decrease vision. In an eye with glaucoma, a build-up of intraocular pressure can cause damage to the optic nerve in the back of the eye. The optic nerve connects the eye to the visual centers in the brain. If glaucoma is undetected and untreated, it can cause permanent vision loss and lead to blindness.
Some patients can have optic nerve damage from elevated pressures, while other patients may have normal pressure readings but can still have damage. This can only be determined by specialized tests.
What causes open angle glaucoma?
Clear aqueous fluid flows behind the cornea within the eye, and drains into a structure called trabecular meshwork, which is between the cornea and the iris (the colored part of the eye). Aqueous fluid brings nutrients to the eye and helps the eye maintain its health. In some patients, this structure can become clogged or less effective, and can slow the drainage of fluid. This can cause a painless rise in intraocular pressure (the pressure reading for glaucoma).
What can I do to protect my sight?
Early detection and treatment is essential for patients who are potentially glaucoma suspects. Therefore, your best defense is to have routine, annual eye exams with an ophthalmologist.
What is it about this disease that makes routine, annual dilated eye exams so important?
The silent nature of this disease is what makes annual eye exams so critical to protecting your sight. “Silent” means that there aren’t any symptoms. Nothing will alert you that you have glaucoma. It slowly damages your optic nerve and your peripheral vision (which is usually not noticeable until it is severe). As the disease progresses, the field of your vision continues to narrow, until it reaches your central vision. When this happens, it becomes noticeable and can cause extensive permanent vision loss. Once you have damage to your optic nerve, caused by glaucoma, it is not reversible. That’s why prevention is the most critical aspect, and this is completely in your power!
Why is dilation of the eye so important?
The optic nerve is located in the back of the eye. In order to properly view this structure for damage, ophthalmologists usually need a dilated pupil for best visualization. When a bright light enters an eye without dilating drops, the pupil naturally constricts to protect the eye. When the pupil constricts, it creates a narrower viewing field for your doctor. A dilated pupil will not constrict when exposed to light, so a thorough evaluation of the back of the eye, including the optic nerve, can be accomplished.
Important points for patients who are already being treated for glaucoma:
- It is extremely important that you do not stop your eye drops! As stated above, glaucoma is a silent eye disease. You won’t know if your eye pressure is elevated until it has caused permanent damage and/or vision loss. This means you should refill your prescription before it runs out!
- Compliance is key! Compliance means not only using your eye drops, but using them as directed. There is a reason why some drops are once a day, and some 3 times a day, et cetera. This is because the duration of the medication lasts a certain period of time, and this timing is different between different eye drops. For instance, if you are told to use a drop twice a day, this means that this particular medication lasts for 12 hours. Consequently, if you go longer than 12 hours without using this eye drop, it may not be optimally controlling your eye pressure.
- Follow the advice of your ophthalmologist! Just like any part of your body, your eyes can change. Both your eye pressure and your eye structure can change with time. With that in mind, your ophthalmologist will tailor a visit schedule based on your particular eyes. These visits may include eye pressure tests, an evaluation of your optic nerve as well as specialized computerized tests for glaucoma, (GDX or optic nerve pictures, and visual field tests which measure your peripheral vision) when indicated. These visits are necessary to ensure that your current drop regimen is still controlling your eye pressure, and therefore protecting your sight. Sometimes it is necessary to change your eye drops or to add another drop to your existing regimen. The only way to know this is to see your ophthalmologist as recommended. For some patients, oral medications can also be used to lower eye pressure. In cases in which eye drops and pills are no longer working to control eye pressure, laser procedures and eye surgery may be an option.
You only have one pair of eyes. Protect your sight by visiting an ophthalmologist annually for a comprehensive, dilated, eye exam!
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