What Is YAG PI (Laser Peripheral Iridotomy)? A Complete Patient Guide

YAG PI stands for Yttrium Aluminium Garnet Peripheral Iridotomy, a laser procedure that creates a tiny, permanent opening near the edge of the iris, the coloured part of the eye. That opening gives fluid inside the eye an additional route to drain, which lowers the risk of a sudden, painful rise in eye pressure known as acute angle closure. If your optometrist or ophthalmologist has told you that your drainage angle is narrow, or you have already had one episode of angle closure in either eye, YAG PI is usually the treatment recommended to protect your sight going forward.

The procedure is done in an outpatient clinic, takes only a few minutes for each eye, and does not require a general anaesthetic. Most patients are in and out of the clinic within an hour, including time for pupil-constricting drops beforehand and a pressure check afterwards.

Why the Drainage Angle Matters

Inside the eye, fluid called aqueous humour is constantly produced and drained through a mesh-like structure at the angle where the iris meets the cornea. In some people, particularly those who are long-sighted, have smaller eyes, or have a family history of angle closure, that angle is naturally narrower than average. As the natural lens inside the eye thickens with age, it can push the iris even closer to that drainage angle, narrowing it further.

When the angle closes completely, even briefly, fluid cannot drain and pressure inside the eye rises rapidly. This is a genuine eye emergency: it can cause severe pain, blurred vision, haloes around lights, nausea, and permanent optic nerve damage if it is not treated within hours. YAG PI is preventative. By creating a second drainage channel through the iris itself, the eye no longer relies solely on the narrow natural angle, and the risk of a closure event falls substantially.

How the YAG PI Procedure Works

• Numbing and pupil drops are applied first, usually to constrict the pupil and stretch the iris tissue, making it easier to treat.

• A special contact lens is placed on the eye to focus the laser and hold the eyelids gently open.

• The YAG laser delivers short, precise pulses to a chosen point on the peripheral iris, usually hidden under the upper eyelid so it is not visually obvious afterward.

• The laser creates a full-thickness opening, confirmed by a small release of fluid or pigment at the treatment site.

• Eye pressure is checked around 30 to 60 minutes after treatment before you go home.

Most people feel only mild pressure or a brief flash of light during treatment rather than pain. Read more about the YAG PI procedure and what it involves on our dedicated page.

Recovery, Side Effects and Follow-Up

Vision is often slightly blurred for a few hours after treatment because of the drops and the laser lens used. Anti-inflammatory drops are usually prescribed for a few days to settle any mild inflammation. Some patients notice a faint line, glare, or crescent-shaped shadow in certain lighting conditions afterward, particularly if the iridotomy is not fully covered by the eyelid. This usually settles or becomes less noticeable within a few weeks as the brain adapts to it.

A follow-up appointment a few weeks later confirms the iridotomy remains open and that eye pressure is stable. In a small number of cases, the opening can partially close over time and require a brief laser touch-up.

Who Is Most Likely to Need YAG PI

Certain groups carry a higher risk of narrow or closing angles and are more often referred for this treatment:

• People who are long-sighted, since their eyes tend to be shorter front to back.

• People of East Asian or Inuit descent, who have a higher population prevalence of narrow angles.

• Women, who are affected roughly twice as often as men.

• Anyone with a close family member who has had angle closure glaucoma.

• Patients found to have a narrow angle on routine examination, even without symptoms.

  
  

Why Experience Matters for This Procedure

YAG PI looks straightforward, but positioning the laser point correctly, judging the right laser energy for each individual iris, and managing patients with very shallow angles or coexisting cataracts all benefit from an experienced hand. Mr Praveen Kumar has performed laser eye treatments, including YAG PI, for more than 35 years and continues to run one of the few dedicated weekly laser clinics still offered within the NHS in the region, alongside his private practice. That volume of experience matters most in the small percentage of eyes where the angle is very narrow, the cornea is cloudy, or a previous iridotomy has partially closed. You can find an overview of the full range of laser and surgical treatments offered on our services page.

Bilateral Treatment and Timing

Because narrow angles are usually a feature of both eyes rather than just one, YAG PI is commonly recommended for both eyes even if only one has caused symptoms so far. Many clinics, including ours, are able to treat both eyes on the same visit, reducing the number of appointments needed and offering protection to the second eye without an unnecessary delay. If only one eye is treated initially, the second eye is typically monitored closely and treated promptly if it also shows signs of narrowing, since the risk of angle closure in the untreated eye remains and can develop with little warning.

Booking a Consultation

If you have been told you have a narrow drainage angle, or you have experienced sudden eye pain, haloes around lights, or blurred vision that resolved on its own, it is worth having your angle formally assessed rather than waiting for a more serious episode. Visit our homepage to find contact details and book a consultation with Mr Praveen Kumar.

Frequently Asked Questions

What does YAG PI stand for?

YAG PI stands for Yttrium Aluminium Garnet Peripheral Iridotomy. It is a laser procedure that creates a small permanent opening in the iris to help fluid drain more freely inside the eye and reduce the risk of angle closure glaucoma.

Is YAG PI painful?

Most patients feel only mild pressure or a brief flash of light rather than pain. Numbing drops are used beforehand, and the treatment itself typically takes just a few minutes per eye.

How long does it take to recover from YAG PI?

Most people return to normal activities the same day. Vision may be slightly blurred for a few hours, and anti-inflammatory drops are usually used for a few days. A follow-up check is arranged a few weeks later.

Will YAG PI affect my appearance or vision permanently?

The opening is normally positioned under the upper eyelid so it is not visible in everyday life. A small number of patients notice glare or a faint line in certain lighting, which usually becomes less noticeable over time.

Who needs a YAG PI procedure?

People with narrow drainage angles found during an eye examination, those who have already had an angle closure episode, and people with risk factors such as long-sightedness, East Asian ethnicity, or a family history of angle closure glaucoma are most commonly referred for this treatment.

Can both eyes be treated with YAG PI on the same day?

Yes, in most cases both eyes can be treated during the same clinic visit, which reduces the number of appointments needed since narrow angles typically affect both eyes rather than just one.