What are Narrow Angles?
“Anatomically narrow angles” is a term used to describe the shape of the drainage angle of the anterior chamber of the eye. Narrow angles are caused by certain anatomical conditions, such as having a shorter than average eye, being hyperopic (far-sighted), or having a growing cataract that gradually narrows the angle over time.
What are the Risk Factors?
The following populations are at a higher risk of having narrow angles:
- Age 60 or Older
- Inuit or East Asian descent
- Family history of angle-closure glaucoma
- Smaller eyes (shorter axial length and smaller corneal diameter)
- Displaced lens
- Progressive increase of cataract
- Use of systemic medications such as topiramate, anticholinergics, and sympathomimetics may also increase risk of angle-closure
The best defense against all forms of glaucoma is regular eye examinations. Experts recommend that adults have a comprehensive eye exam every two to four years after age 40, and annually starting at age 60. If you’ve been told you have narrow angles, you should have an eye examination every year, regardless of age.
How Are They Diagnosed?
Narrow angles are diagnosed with a physical examination using gonioscopy and/or an OCT of the anterior segment. Careful examination of the angle anatomy is important, as many patients with potentially occludable angles do not have any symptoms.
During an eye exam, your vision will be tested for refractive errors (farsightedness or nearsightedness). Peripheral vision will also be checked, as well as eye movement and coordination, and intraocular pressure. If at least half of the trabecular meshwork is visible, you’re not at imminent risk and will be advised to have annual exams. But if more than 50% is obscured, the next step is usually a peripheral laser iridotomy to prevent an acute angle-closure attack.
What is Acute Angle-Closure?
Patients with narrow angles are at high risk of developing acute angle-closure. Acute angle-closure is a medical emergency that may result in permanent vision loss if not addressed immediately. Acute angle-closure occurs when the aqueous humor movement from behind the iris to the front is so blocked that the pressure behind the iris pushes it against the meshwork and stops all aqueous outflow. This usually occurs in darken rooms when the pupils are dilated. This results in an increase in eye pressure that may result in permanent damage to ganglion cells in the optic nerves.
What are the Symptoms of Acute Angle Closure?
- Nausea and vomiting
- Severe eye pain
- Profuse tearing
- Bigger and irregular pupil shape
- Redness of the sclera
- Blurred vision and/or seeing halos around lights (due to the cornea being swollen)
What is Angle-Closure Glaucoma?
When the anterior chamber’s angle is chronically narrow, patients may develop both acute angle-closure glaucoma and chronic angle-closure glaucoma.
Angle-closure glaucoma describes damage to the optic nerve resulting from adhesional closure of the anterior-chamber angle secondary to elevated IOP. This may occur in an acute or chronic form. If acute closure of the angle persists or if the angle closes from prolonged or repeated contact between the iris and the trabecular meshwork, this often leads to peripheral anterior synechiae and functional damage to the angle.
Glaucoma is the leading cause of irreversible blindness worldwide, and angle-closure is responsible for 50% of glaucoma blindness.
Many patients with anatomically narrow angles are asymptomatic. If you are at risk for developing ACG, your ophthalmologist may recommend treatment with a laser iridotomy.
What Happens During Laser Iridotomy?
- Before the laser surgery, the eye is anesthetized with numbing drops and an anti-inflammatory drop may be given.
- A contact lens is placed on the eye and a laser beam is aimed.
- Multiple laser shots are given into the iris to create a drainage hole.
The surgery is not painful, but the patient may experience slight discomfort or feel “pop” type sensations. Ten minutes after the procedure, the patient’s eye pressure is checked.
Request an Appointment in San Jose or Gilroy, California
If you are experiencing any of the signs and symptoms associated with narrow angles, contact South Bay Retina today. Dr. Narain is an experienced ophthalmologist who can perform laser iridotomy and help you feel like yourself again. Schedule at one of our two locations in the South Bay: San Jose and Gilroy. Call (408) 294-3534 for our San Jose and Gilroy office. You can also click the button below to schedule an appointment online.