What are "narrow angles" and why are they a problem?
The eye is filled with a fluid that nourishes the eye and helps it keep its shape. The
fluid drains out of the eye between the iris, the colored part of the eye, and the
cornea, the clear part that covers the front of the eye. The balance between how
much fluid is made and how much drains from the eye determines the pressure
within the eye.
In some people, the eye is small. The iris and the cornea are close together forming
a narrow angle. The angle is at risk of closing, often when the pupil is dilated. This
can happen by itself, or be caused by medicine. When the angle is closed, the
drainage tract is sealed off. When the fluid cannot leave the eye, the pressure in the
eye rises sharply. As the pressure rises, the eye becomes red and painful and you
may notice blurred vision, haloes around lights, a severe headache, and nausea.
This is known as a "glaucoma attack" or acute angle-closure glaucoma. This is an
eye emergency. If the pressure is not relieved, there may be permanent damage or
Can angle-closure glaucoma be prevented?
A laser procedure, known as a peripheral iridotomy, can be done. A small hole is
made in the edge of the iris to create a new drainage path for the eye fluid. The
hole is about the size of a pinhead, and is often placed in the upper part of the iris so
that it cannot be seen under the eyelid. Once this hole is created, it is very rare to
have an angle-closure attack.
How is the laser iridotomy performed?
We’ll schedule you to arrive at the clinic 1 hour before the laser treatment for a
pressure check and to have several drops put in your eyes. One drop, pilocarpine,
will make your pupil smaller and will help to stretch your iris to make it easier for
the laser to make the hole. Pilocarpine can cause a slight aching in your brow area
(headache). The other drop will help to keep the eye pressure low during and after
The laser treatment will be done after the drops have been in your eyes for about an
hour. You will sit at a machine that looks like the slit-lamp microscope used for
your eye exam in the clinic. The laser is attached to this machine. A drop of
anesthetic will be put in your eye. The doctor will put in a special contact lens.
You will focus on a target light in front of your other eye, and the doctor will “fire”
the laser when you are in the correct position. Most patients say that they feel a
slight pop or shock when the laser is “fired”, but say that it is not painful. The
doctor may push slightly on your eye with the contact lens if there is any bleeding
or oozing in your eye. The treatment takes only a few minutes for each eye that is
You will also receive drops after the laser treatment. You will be given a
prescription for drops to be used for the next 5 days, 4 times a day.
Will I have any restrictions after the laser?
There are no restrictions on your activities after your laser treatment.
What should I watch for after laser treatment?
Most people notice a slight blurring of vision because of the gel used with the
contact lens. You may expect a slight redness or a scratchy feeling in the treated
eye for a few days. You may also have a slight headache after the laser treatment.
What are the risks in peripheral iridotomy?
One risk of laser iridotomy is that your iris might be hard to go through and may
need more than one treatment session. The hole in your iris may close, and may
need to be opened again. There may be a small amount of bleeding in the eye after
the treatment. This will be stopped by putting pressure on the eye with the contact
lens. The laser could be fired at the wrong place in the eye, but this is very rare.
Your pressure may go up after the laser treatment for a short time. If this happens,
other medicines can be used to bring down the pressure in your eye. Rarely, glare
or light reflections may be seen afterwards.
Do I really need to have this laser treatment?
A peripheral iridotomy will prevent you from having a glaucoma attack. Your eye
doctor feels that you are at risk. No one can predict when or if you will have an
attack. If you choose not to have this treatment, you need to know the risks and
symptoms of angle-closure so that you can seek treatment from an ophthalmologist
An eye that has had an attack of angle-closure may suffer permanently increased
pressure, vision loss, or blindness. In contrast, a laser iridotomy is safe and
effective, with few risks.
If you have a sudden loss of vision or a lot of pain beyond what was described
above, please contact the clinic staff at:
University Station Eye Clinic, 8 a.m. to 4:30 p.m., Monday through Friday
When the clinic is closed, your call will be forwarded to the hospital paging
operator. Ask for the “Eye Resident on Call”. Give the operator your name and
phone number with area code. The doctor will call you back.
If you live out of the area, call 1-800-323-8942 and ask to be transferred to the
Please call if you have any questions or concerns
Your health care team may have given you this information as part of your care. If so, please use it and call if you
have any questions. If this information was not given to you as part of your care, please check with your doctor. This
is not medical advice. This is not to be used for diagnosis or treatment of any medical condition. Because each
person’s health needs are different, you should talk with your doctor or others on your health care team when using
this information. If you have an emergency, please call 911. Copyright © 1/2016 University of Wisconsin Hospitals
and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#4589