WHAT ARE NARROW ANGLES (OR CLOSED ANGLES)?
The natural drainage system of the eye is located in the anterior chamber ‘angle’ between the cornea (the clear part of the eye) and the iris (the colored part of the eye). If the angle is open, most or all of the drainage system is visible; however, if the angle is narrow then only portions of the drainage system are visible.
HOW TO CHECK FOR NARROW ANGLES?
The most common way to identify ‘narrow angles’ is by a particular component of the eye exam called gonioscopy. In this test, an ophthalmologist uses a mirrored lens to examine the drainage system of the eye. In more unusual cases, an ultrasound could be performed to verify a narrow angle as shown in the picture above.
DOES HAVING NARROW ANGLES MEAN YOU HAVE GLAUCOMA?
When the ‘angle’ is narrow, patients are at risk of developing both acute angle closure glaucoma and chronic angle closure glaucoma. It is important however to understand that being at risk for glaucoma and having glaucoma are different.
Glaucoma refers to damage of the optic nerve, the nerve that connects the eyeball to the brain. This nerve damage results in irreversible loss of vision that may or may not be noticeable at first but can progress. There are several terms that help differentiate between narrow angle with or without glaucoma.
‘Primary angle closure suspect’ (Often referred to as ‘anatomical narrow angle’) refers to when an eye with narrow angles without evidence of glaucoma. These patients will still need to be monitored for the development of glaucoma in their lifetime.
‘Primary angle closure’ refers to an eye with narrow angles that has additional risk factors for glaucoma such high eye pressure or scar tissue in the angle. These patients may warrant treatment to decrease the chance of developing glaucoma.
‘Primary angle closure glaucoma’ refers to an eye with narrow angles that has evidence of damage from glaucoma. These patients require treatment and monitoring to prevent the progression of glaucoma.
Primary angle closure glaucoma may be acute or chronic.
WHAT IS ACUTE ANGLE CLOSURE GLAUCOMA?
Acute angle closure glaucoma occurs when narrowing of the anterior chamber angle causes blockage of the drainage system leading to a SUDDEN increase in eye pressure.
This is an eye emergency. Symptoms can include severe eye pain, headache, blurry vision, tearing, and redness. Rapid treatment to decrease the intraocular pressure and break the attack of angle closure is needed to preserve vision.
WHAT IS CHRONIC ANGLE CLOSURE GLAUCOMA?
The anterior chamber angle is composed of the iris and cornea. When the angle is narrow and these structures are very close together, scar tissue may form between them and overly the drainage apparatus of the eye. If enough of this scar tissue is present, high eye pressure and glaucoma develop over time in a process termed chronic angle closure glaucoma. Although in many people this condition is slowly progressive, acute increase of eye pressure may occur within the context of chronic angle closure glaucoma.
NARROW ANGLE RISK FACTORS
Risk factors for narrow angles include:
- Being farsighted (wear + prescription)
- Older age
- Female gender
- Of Asian or Inuit descent
- A family history of narrow angles
- Significant cataract
WHAT TO AVOID IF YOU HAVE NARROW ANGLES
It is important to avoid dilating drops until you are cleared for dilation by your eye doctor. Other medications should also be avoided, if possible, until cleared by your doctor. Medications that warn regarding ‘glaucoma’ as an adverse effect include:
- Decongestants/Cold medications
- Allergy medications
- Anxiety and depression medications (Do NOT stop these without discussing with your doctor as this can result in withdrawal symptoms)
- Reflux/nausea medication
- Incontinence/Overactive bladder medication
These medication concerns should be discussed directly with your doctor.
It is important to get regular eye examinations, especially if you are at a higher risk of narrow angles. Please contact us today to schedule an appointment with a Wills Eye specialist and to analyze your own risk of narrow angles, and if you are experiencing the symptoms of an acute angle-closure attack visit your nearest emergency room as soon as possible.