Laser Peripheral Iridotomy (LPI)

Laser peripheral iridotomy is a laser procedure that makes a small opening in the iris (the colored part of the eye). The procedure aims to improve the drainage canal in the eye and prevent acute angle closure.

When is Laser peripheral iridotomy necessary?

Typically, there are two situations where a laser iridotomy may be required.

A laser iridotomy is necessary when the fluid drainage system of the eye is completely blocked. A muscle behind the iris constantly produces a fluid called aqueous, which then drains through a sponge-like drain system called the trabecular meshwork. Blocking this system causes the pressure in the eye to rise, which can permanently damage the optic nerve and result in vision loss. This process is called acute angle-closure attack, which is a medical emergency.

A laser iridotomy creates a new route for fluid to flow from behind the iris to the outflow drainage system of the eye.  Prevention of angle-closure glaucoma is also an indicator for a laser iridotomy. Some individuals may have a natural tendency to be at risk of angle-closure due to the shape of their eye. A laser iridotomy may be advised to reduce the risk of an attack occurring in future.

What are the symptoms of an acute angle-closure attack?

Not all people with angle-closure glaucoma experience an attack. When angle-closure glaucoma develops slowly, there are no obvious symptoms. However, your doctor may recognise your risk for angle-closure glaucoma before you experience any symptoms.

Symptoms of an angle-closure glaucoma attack are:

  • Headache or eye pain

  • Blurred vision

  • Haloes around lights

  • Red eye

  • Nausea and vomiting. 

If pressure is not relieved within a few hours, there may be permanent vision loss.

What are the risk factors for angle-closure glaucoma?

The major risk factors for angle-closure include;

  • Age

  • Family history of glaucoma

  • Being very long-sighted

  • Asian ethnicity

How do I prevent an angle-closure attack?

An eye at risk for angle-closure glaucoma can be detected as part of a routine eye exam. Using a mirrored lens, your Ophthalmologist can see if the trabecular meshwork is in danger of being blocked.  A laser iridotomy may be recommended to prevent an angle-closure glaucoma attack. 

What can I expect from a laser iridotomy?

A laser iridotomy is usually a quick procedure performed in the clinic on a machine similar to a slit lamp microscope. Your Ophthalmologist will give you eye drops to numb your eye and place a contact lens on your eye to precisely focus the laser.  A laser iridotomy only takes a few minutes.  You may see a bright light like a photographer’s flash. 

In general, there are no activity restrictions following the laser treatment, although you should have someone drive you home after the procedure. The opening made by an iridotomy is about the size of a pinhead.  The opening is so small, you are unable to see it with the naked eye. The laser opening is also usually performed at the top of the iris, so it is covered by the upper eyelid.

What are the risks?

Loss of vision after laser iridotomy is extremely rare. The main risks of the laser procedure are: 

  • The iris may be difficult to penetrate, requiring more than one treatment.

  • A blood vessel in the iris may bleed.

  • Glare may very occasionally occur as extra light can enter the eye through this small laser opening.

  • Intraocular pressure spikes