Summary about Disease
Angle-closure glaucoma, also known as closed-angle glaucoma or narrow-angle glaucoma, is a type of glaucoma that occurs when the iris (the colored part of the eye) blocks the drainage angle, preventing fluid (aqueous humor) from exiting the eye. This leads to a rapid increase in intraocular pressure (IOP), which can damage the optic nerve and cause vision loss. It can occur suddenly (acute) or gradually (chronic).
Symptoms
Symptoms can vary depending on whether the angle closure is acute or chronic.
Acute Angle-Closure Glaucoma:
Severe eye pain
Sudden blurred vision
Halos around lights
Redness of the eye
Headache
Nausea and vomiting
Chronic Angle-Closure Glaucoma:
Gradual vision loss (often unnoticed in the early stages)
Eye discomfort
Causes
The primary cause is the physical blockage of the drainage angle by the iris. Factors contributing to this blockage include:
Anatomical Predisposition: People with shallow anterior chambers (the space between the cornea and iris) are more susceptible.
Pupil Dilation: Dilation of the pupil can cause the iris to bunch up and block the angle, especially in people with narrow angles.
Age: The risk increases with age as the lens thickens, pushing the iris forward.
Farsightedness (Hyperopia): Farsighted eyes tend to be smaller, increasing the risk.
Certain Medications: Some medications (e.g., decongestants, certain antidepressants) can dilate the pupil and trigger an attack.
Eye Trauma or Inflammation: Can cause scarring and angle closure.
Medicine Used
Medications are used to lower intraocular pressure (IOP) and relieve the angle closure. Common medications include:
Pilocarpine: A miotic that constricts the pupil, pulling the iris away from the angle (used with caution in some cases).
Beta-blocker eye drops (e.g., timolol): Reduce aqueous humor production.
Alpha-adrenergic agonists (e.g., brimonidine): Reduce aqueous humor production and increase outflow.
Carbonic anhydrase inhibitors (e.g., dorzolamide, acetazolamide): Reduce aqueous humor production.
Prostaglandin analogs (e.g., latanoprost) : While generally used for open angle glaucoma, they can sometimes be used adjunctively in chronic angle closure after angle opening procedures.
Hyperosmotic agents (e.g., mannitol, glycerol): Used intravenously to rapidly lower IOP in acute attacks. Note: Laser iridotomy is often performed to create a new drainage pathway.
Is Communicable
No, angle-closure glaucoma is not communicable. It is not caused by an infection and cannot be spread from person to person.
Precautions
Regular Eye Exams: Crucial for early detection, especially for those with risk factors.
Avoid Medications That Dilate Pupils: Be cautious with medications that can dilate the pupils, especially if you have narrow angles. Consult your doctor or pharmacist.
Be Aware of Symptoms: Seek immediate medical attention if you experience sudden eye pain, blurred vision, or halos around lights.
Genetic Testing and Counseling If there is a family history.
How long does an outbreak last?
An acute angle-closure attack can last for several hours if untreated. The damage from elevated IOP can be permanent. Chronic angle closure can develop slowly over time.
How is it diagnosed?
Tonometry: Measures intraocular pressure (IOP).
Gonioscopy: Uses a special lens to visualize the drainage angle and determine if it is open or closed.
Visual Field Testing: Assesses peripheral vision loss.
Optical Coherence Tomography (OCT): Scans the optic nerve to detect damage.
Slit-Lamp Examination: A comprehensive eye exam to assess the overall health of the eye.
Timeline of Symptoms
Acute Angle-Closure: Symptoms develop rapidly over minutes to hours (severe pain, blurred vision, halos).
Chronic Angle-Closure: Symptoms develop gradually over months or years, often going unnoticed until significant vision loss occurs.
Important Considerations
Emergency Situation: Acute angle-closure glaucoma is a medical emergency requiring immediate treatment to prevent permanent vision loss.
Prophylactic Treatment: People with narrow angles may be advised to undergo laser iridotomy to prevent angle closure, even if they have no symptoms.
Lifelong Monitoring: Once diagnosed, angle-closure glaucoma requires ongoing monitoring and treatment to control IOP and prevent further damage.
Second Eye: Often both eyes have the anatomical predisposition to angle closure. The second eye is often treated prophylactically after an angle closure episode in the first eye.