Most Glaucomas are painless. However, there are a few types of glaucomas that cause sudden loss of vision and severe pain in the eye, leading to an eye emergency situation.
Read today’s post about how acute glaucomas manifest and how they can be treated.
Today is Day # 3 of World Glaucoma Week 2022. Let’s discuss a relatively uncommon type of glaucoma known as “acute glaucoma”.
What is acute glaucoma?
Acute glaucoma is a condition in which the pressure in the eye rises suddenly, causing severe pain and blurring of vision. This is also known as a “Angle closure glaucoma” or “closed angle glaucoma”.
Since acute glaucoma often occurs in patients with a “narrow irido-corneal angle” it is also known as “narrow angle glaucoma”.
What is a “Narrow Irido-corneal angle”?
As I’ve discussed in a previous post, there is a clear fluid that circulates in our eyes known as aqueous humor. Aqueous humor is formed behind the eyes and moves anteriorly through the pupil and leaves the eye through the trabecular meshwork.
Here’s a video showing the normal flow of aqueous humor.
Any obstruction to drainage of the aqueous humor leads to rise in eye pressure.
Now this obstruction could be in the trabecular meshwork, as in cases of “open angle glaucoma” in which the eye pressure rises slowly and the vision loss occurs gradually, without pain.
If the obstruction is because of a “narrow iridocorneal angle”, the space between the iris and the cornea is narrow. Due to certain triggers, the “narrow angle” becomes a “closed angle” and the eye pressure rises rapidly leading to pain and sudden loss of vision. This video explains the difference between the two broad types of glaucoma.
What are the triggers that cause a narrow angle to become a closed angle?
For a narrow angle to proceed to angle closure, the pupil needs to be in a semi dilated state. Following are the triggers that can precipitate a “closed angle attack”.
1. Dark rooms
Places with low ambient light such as cinema halls, or any dark conditions cause dilatation of the pupil. This can trigger an attack.
2. Emotional distress
Emotional distress is a known trigger for an acute glaucoma attack.
3. Pharmacological pupil dilatation
Sometimes, for eye examination, your eye doctor will instill certain medications in your eyes to dilate your pupil to examine your retina. If these medications are instilled in patients who have a narrow iridocorneal angle, an attack may be precipitated.
What are the symptoms of an acute glaucoma attack?
Patients suffering from an acute attack of glaucoma may present with
- Severe eye pain
- Nausea and Vomiting
- Blurring of vision
- Eye Redness
- Colored haloes
Who is prone to develop acute glaucomas?
There are certain risk factors that make a person prone to develop acute painful glaucoma.
1. Structure of the eye
Every person has a unique structure of their eyes. In some patients, the “Irido-corneal angle” is narrow. As a result the clear fluid in the eye known as aqueous humor gets obstructed, leading to a sudden rise in eye pressure.
A narrow iridocorneal angle is more commonly found among women, therefore the risk of developing acute glaucoma is higher among women.
3. High hypermetropia
Hypermetropia refers to a “plus” spectacles power. People who have a plus power of glasses have relatively smaller eyes compared to those with a minus power or no power. Smaller eyes have a narrow “irido-corneal angle” which is a major predisposing factor for acute glaucoma.
4. Advanced cataracts
If a cataract is not operated on type, it progresses into a “hypermature” state. A hypermature cataract can lead to “lens-induced glaucoma” in which the cataractous lens or its particles obstruct the flow of the aqueous humor leading to a sudden rise in eye pressure.
How is an acute glaucoma attack treated?
An acute glaucoma attack is a medical emergency as the patient is often in severe pain and if left untreated can lead to severe permanent loss of vision.
Therefore, the patient is immediately admitted to a hospital and treatment is started.
The priority during an acute glaucoma attack is to immediately lower the eye pressure. Various medications are given to lower the pressure, that includes intravenous mannitol, oral glycerol, tablets of eye pressure lowering drugs and topical medications in the form of eyedrops.
An acute attack may take 24-48 hours to resolve with proper treatment.
Can acute glaucoma attack be prevented?
Yes! There is a procedure known as “laser iridotomy”, that uses a laser to create an alternate passage for aqueous to flow in case the angle closes ever again in future. This would prevent any further attacks.
Also, following an angle closure attack, the fellow eye is also treated with laser so that there is an alternate passage for the aqueous flow and the never progresses to an acute attack.
Here’s an animated video explaining the laser iridotomy procedure.
I hope I have helped you understand acute glaucomas through this post. If you have any questions, feel free to comment below or email me at firstname.lastname@example.org
I’ll see you tomorrow with another glaucoma related post. Till then take good care of your eyes and stay healthy!