Narrow Angles & Angle Closure Glaucoma
- Posted on: Sep 16 2019
This material will help you understand narrow angles and how they are treated.
Eye words to know:
- Optic nerve: A nerve at the back of your eye that connects to your brain. The optic nerve sends light signals to your brain so you can see.
- Aqueous humor (“aqueous”): Clear liquid inside the front part of our eyes. It nourishes the eye and keeps it inflated. (Aqueous is different from tears, which are outside the eye.)
- Drainage angle: The area of the eye where the aqueous humor drains from the front of the eye.
- Iris: The colored part of your eye. It controls the size of your pupil to let light into your eye.
What are narrow angles?
Narrow angle is a term used to describe the shape of the drainage angle of the eye. Narrow angles are more common in people who are farsighted. This is because farsighted people have shorter eyes than those who are nearsighted or those who do not need glasses at all.
A shorter eye can mean that there is less room in the front of the eye to house both the lens and iris. (The iris is the colored part of the eye.) This can make things crowded pushing the iris towards the cornea. (The cornea is the clear front part of the eye). The drain of the eye lies between the cornea and the iris. When the iris gets pushed forward, it can crowd the drain. This puts you at risk for angle-closure glaucoma.
What is angle-closure glaucoma?
Angle-closure glaucoma occurs when the drain of the eye becomes blocked, causing pressure to rise inside the eye. The iris gets pushed forward inside the eye, closing off the drainage angle completely. If this happens quickly, it is called acute angle-closure glaucoma. If an eye doctor does not treat acute angle-closure glaucoma quickly, you can lose vision.
When the drainage angle of the eye is blocked slowly, the pressure builds up over a longer period. This is called chronic angle-closure glaucoma. If an eye doctor does not treat chronic angle-closure glaucoma, you can also lose vision. Having narrow angles puts you at risk for developing both kinds of angle-closure glaucoma.
Do I have symptoms of narrow angles?
You would not have any symptoms from narrow angles unless you developed an attack of acute angle-closure glaucoma. Acute angle-closure glaucoma can give you sudden vision loss, with or without these symptoms:
- Hazy/foggy vision
- Severe eye and/or brow pain
- Headache, nausea, vomiting
- Seeing rainbow-colored rings or halos around lights
An acute angle-closure glaucoma attack is an emergency. It must be treated quickly to prevent loss of vision. If you have these symptoms, call an ophthalmologist right away or go to a hospital emergency room.
Some people do not have symptoms with their closed-angle glaucoma, but high pressure is still damaging the optic nerve. This is called chronic angle-closure glaucoma. This condition often requires surgery. Ophthalmologists know that reducing eye pressure as soon as possible can save your vision.
How are narrow angles treated?
Not all narrow angles need treatment. Sometimes, your eye doctor does not feel you are at risk for an acute angle-closure attack. S/he will just continue to monitor your eye.
Other times, your angles are narrow enough that you are at high risk of developing an acute angle-closure attack. In these cases, your eye doctor will recommend a laser treatment called a laser peripheral iridotomy.
Laser Peripheral Iridotomy (LPI)
This laser creates an escape valve inside your eye to prevent an acute angle-closure attack. If fluid builds inside the eye, there is a way for the fluid to exit without causing your eye pressure to rise to an unsafe level.
The laser makes a little hole in the iris. This is like what you would do if a house were flooding from the basement. You would punch a hole through an upstairs window to let the water escape. Once you have had the laser hole, or laser peripheral iridotomy, you will not have an acute attack as you already have an escape valve in case your iris ever tries to close off your drain completely.
Laser iridotomy only takes a few minutes. Here is what happens:
- Your eye will be numbed with eye drops. You may be given other eye drops as well to make your pupil very small.
- Your ophthalmologist will place a special contact lens on your eye. This serves as a guide for the laser.
- Using the laser, your ophthalmologist will precisely create a tiny hole in your iris. You may feel a stinging sensation as the laser is used.
- After the procedure, your vision may be blurry for a couple of hours. Plan to have someone drive you home after the surgery.
Risks of LPI
Like any surgery, laser iridotomy carries risks. Fortunately, problems or complications are uncommon. Risks may include:
- Headache or brow pain
- A sudden increase in eye pressure
- Eye redness, swelling, or pain
- Bleeding in the eye
- Blurry vision or seeing streaks of light
- Cataracts (clouding of the eye’s naturally clear lens)
- The need to have laser iridotomy again
Your ophthalmologist will talk with you about the risks and benefits of laser iridotomy.
If your eye doctor has recommended laser treatment, it is important to avoid things that would dilate your pupil before you have your treatment. When your pupil is dilated, the iris tissue bunches up inside the drain even more. This can cause an acute attack.
Over the counter, cold medicines and some medicine for motion sickness can dilate the pupil. You should not take these unless you have already had the laser treatment. You should read all new over the counter and prescription medication labels carefully. If it says that you should not take it if you have glaucoma, do not take it. (The kind of glaucoma they are warning about is the kind for which you are at risk).
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