According to the Glaucoma Research Foundation (GRF), laser peripheral iridotomy (LPI) has been a standard procedure for treating and preventing closed-angle glaucoma since 1984. Here, a brief animated video produced by the American Academy of Ophthalmology describes why LPI is used and what’s involved in the procedure.*

Eye pressure and glaucoma 

Increased internal eye pressure can lead to glaucoma. LPI lowers the pressure by improving fluid drainage.

• Normally, excess eye fluid (aqueous humor) leaves the eye via a natural drainage system called the trabecular meshwork. 
• This happens in what’s called the drainage angle, or the space between the iris and cornea.
• Eye pressure can increase if the fluid doesn’t drain properly. This elevated pressure can damage the optic nerve, leading to glaucoma.

LPI for narrow drainage angles 

LPI is often advised when the drainage angle becomes too narrow for fluid to adequately drain from the eye. 

• When the drainage pathway becomes completely obstructed, eye pressure can quickly rise.
• A sudden spike in eye pressure is called a closed-angle glaucoma attack, or acute angle-closure glaucoma, and is a medical emergency.

LPI can help prevent acute angle-closure from developing and is typically used to treat any closed-angle attack.

How LPI works 

LPI is generally an outpatient procedure that takes 5-10 minutes to perform.

• Eye drops are applied before the procedure to numb the eyes and reduce the pupils.
• A beam of light creates a hole in the perimeter of the iris, roughly the size of a pinhead.
• Fluid trapped behind the iris can then move to the front of the eye, relaxing the iris.
• As the drainage angle reopens, fluid is able to exit the eye, lowering pressure.

Possible risks 

Potential risks of LPI include, for example:

• Increased eye pressure (temporary or permanent)
• Iris or corneal swelling
• Clouded cornea
• Laser opening closing up
• Eye pain and/or bleeding
• Vision loss

Frequently asked questions

People should raise any questions or concerns about LPI or their general eye health with their eye care provider. Here are answers to some commonly asked questions regarding LPI.

Who’s a candidate for LPI?

• LPI is advised for people with at least 50% angle closure and either elevated eye pressure or glaucoma. 
• LPI as a preventive measure may be advised for people who have angle closure with normal eye pressure and no damage to their optic nerve.

What if LPI doesn’t work?

LPI may fail to open the drainage angle in approximately 25% of cases. If this happens, further laser procedures or other treatments may be needed. 

Will LPI improve my vision and will I still need glaucoma medication?

• No, LPI will not improve vision, as it is meant to preserve vision and prevent glaucoma.
• Yes, usually patients will still need their glaucoma eye drops if they were taking them before the procedure.

How long does LPI’s effect last?

While the angle generally widens after LPI, changes can happen to the area as a normal part of aging. A cataract could form that blocks the angle and requires removal.

Even if you and your doctor decide that LPI isn’t right for you, some form of treatment is necessary to lower eye pressure in order to prevent vision loss. 

*Sharp Healthcare. (2017, February 16). Laser Iridotomy for Glaucoma [Video file]. Retrieved from https://www.youtube.com/watch?v=XL3p3aiRoBU