Definition

Glaucoma is characterized by damage to the optic nerve, primarily resulting from disruptions in the aqueous humor system within the eye. When the normal flow of this eye fluid is obstructed, it leads to a buildup of aqueous humor, consequently increasing intraocular pressure. This accumulation can then cause damage to the optic nerve, culminating in glaucoma. Although increased eye pressure is commonly associated with glaucoma, certain types of glaucoma can occur even with normal eye pressure.

Acute glaucoma is a particularly critical form of glaucoma that necessitates immediate medical treatments. This condition arises from the sudden closure of the anterior chamber angle, which, although potentially reversible, demands prompt treatment. Approximately 0.7% of individuals over the age of 40 experience angle-closure glaucoma, with a higher prevalence observed in Asian populations.

Causes

Under normal conditions, the anterior chamber angle of the eye separates the iris from the cornea. However, when this angle closes—especially abruptly—it can lead to acute glaucoma, which presents symptoms such as pain and eye redness.

Acute glaucoma results from the sudden closure of the anterior chamber angle, causing the aqueous humor to accumulate and leading to an increase in intraocular pressure. This elevated pressure can then inflict damage on the optic nerve. Without timely and appropriate treatment, this condition can result in irreversible blindness.

The closure of the anterior chamber angle may occur due to various mechanisms, often involving disruptions in the flow of eye fluid and the rapid or frequent dilation of the pupil. The following situations may contribute to this condition:

• Spending time in a dark room
• After receiving medication to dilate the pupil (via specific eye drops)
• Experiencing intense emotions such as excitement or stress
• Taking certain medications, including antidepressants or antihistamines

In addition to these factors, several comorbidities may also precipitate acute glaucoma, such as:

• Cataracts
• Ectopic lenses (misalignment of the eye lens)
• Diabetic retinopathy, a complication of diabetes
• Ocular ischemia or narrowing of the blood vessels in the eye
• Uveitis or eye inflammation
• Ocular tumors

Risk Factor

The size of the eye varies among individuals. People with smaller eyes may have less space within the eye structure (including the ciliary body, lens, and iris), making it easier for the flow of eye fluid to be disrupted. Consequently, individuals with this particular eye structure or size are at an increased risk of developing acute glaucoma.

Several conditions further elevate the risk of acute glaucoma, including:

• Female
• Age over 60 years
• Presence of eye conditions such as nearsightedness or cataracts
• Prior history of systemic diseases, including diabetes, hypertension, heart attacks, and sickle cell anemia
• Previous eye surgeries
• Estrogen hormone deficiency, such as in individuals who have undergone surgery to remove both ovaries
• Prolonged use of corticosteroid medications

Symptoms

Symptoms of acute glaucoma typically manifest suddenly and may include: 

• Eye redness
• Eye pain
• Headaches
• Blurred vision
• Nausea
• Vomiting
• The perception of halos (seeing circular light shadows)

Diagnosis

The diagnosis of acute glaucoma is established through symptom history and physical examination. During the interview to inquire patients’ medical history, the doctor may ask about their recent activities such as watching television, reading, or spending time in a dark room, as well as the use of eye drops intended to dilate the pupils.

During the physical examination, the doctor will look for symptoms such as eye redness, eye pain, and signs of elevated intraocular pressure. Several additional eye physical examinations may also be conducted.

To confirm the diagnosis, the following tests may be performed:

• Gonioscopy. This eye examination assesses the structure of the eye, particularly the drainage angle, to identify any abnormalities.
• Tonometry. This test measures intraocular pressure, which is typically elevated in cases of acute glaucoma.
• Ophthalmoscopy. This examination allows the doctor to inspect the inside of the eye, including the retina, to assess for damage.

Management

Immediate treatment is crucial for acute glaucoma, as failure to address the condition promptly can lead to blindness. Anyone experiencing symptoms of acute glaucoma should be taken to a hospital for professional medical care without delay. Initial treatment typically involves administering eye drops to constrict the pupil and medications to reduce tear production.

Patients are often positioned lying down, allowing gravity to help move the lens down or back. This position helps reduce intraocular pressure. Alongside positioning, pain relievers and anti-nausea medications are administered. Once the intraocular pressure has decreased slightly, the doctor may recommend laser procedures such as:

• Iridotomy. A small hole is created in the iris to facilitate the outflow of fluid within the eye.
• Iridoplasty. The iris's edge is pulled away from the drainage ducts to improve fluid flow.

If these measures do not resolve the condition or if acute glaucoma is related to other eye diseases, surgical intervention may be necessary. Surgical options include cataract surgery, synechialysis (removal of adhesions in the eye), trabeculectomy (creating an opening in the eye to allow fluid to drain), or the installation of a glaucoma drainage device.

Complications

Acute glaucoma can be managed effectively in 60-75% of cases without leading to permanent eye damage. However, it is important to recognize that acute glaucoma can result in serious complications. If the condition is not diagnosed or treated in its early stages, temporary vision loss may occur. This loss typically starts with peripheral vision impairment (narrowed field of view) before progressing to central vision. Additionally, a severe form known as malignant glaucoma may develop, where the condition does not respond to surgical treatment, potentially leading to blindness.

Prevention

Preventive measures for acute glaucoma include:

1. Maintaining Eye Health: Start eye care early by consuming foods rich in vitamin A and scheduling regular eye examinations. Annual eye check-ups are particularly recommended for individuals at high risk.
2. Understanding Family History: Since acute glaucoma risk can be hereditary, it is essential to be aware of any family history of eye conditions. Regular screening or health check-ups, ideally once a year, can help in early detection.
3. Regular Exercise: Engaging in regular physical activity can enhance overall health, including eye health. Consult a doctor to design an exercise regimen suitable for your condition.
4. Using Eye Protection: If your occupation or activities put your eyes at risk of injury, wearing protective eyewear is vital. Eye injuries can trigger acute glaucoma.

When to see a doctor?

Acute glaucoma is a medical emergency requiring immediate intervention. If someone exhibits symptoms of acute glaucoma, they should be promptly referred to an eye specialist for further evaluation and management.

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