YAG laser iridotomy creates a small opening in the peripheral iris so that aqueous humour can pass from behind the iris to the front, relieving or preventing pupillary block in angle-closure disease. It is a quick outpatient procedure that glaucoma clinics perform regularly. This article describes the principle, the typical sequence, settings that are discussed in practice, lenses and complications, and what to look for in a Nd:YAG laser.
Why laser iridotomy is performed in angle-closure
In primary angle closure the iris is pushed forward against the trabecular meshwork because fluid cannot flow freely through the pupil. Pressure behind the iris rises, the angle narrows and intraocular pressure can spike suddenly. A small peripheral hole in the iris equalises the pressure between the chambers and lets the iris fall back.
The procedure is used both to treat acute and subacute angle closure, usually after medical treatment has lowered the pressure, and prophylactically in narrow-angle eyes judged at risk. Selection, timing and follow-up are decisions for the treating glaucoma specialist.
How YAG laser peripheral iridotomy is performed
A topical anaesthetic is applied and the pupil is often constricted with a miotic to thin and stretch the peripheral iris. An iridotomy contact lens, which focuses the beam and stabilises the eye, is placed on the cornea. The surgeon usually selects a site in the upper iris under the eyelid, in a crypt or thin area, away from visible vessels.
The Nd:YAG pulse photodisrupts the tissue; several pulses may be needed until the opening is seen with a flow of pigment and a view of the lens capsule. Anti-inflammatory drops and a pressure check follow, according to the clinic protocol. Dark, thick irides are sometimes pretreated with another laser, which is the surgeon's choice.
Typical settings and laser features
Published practice often uses energy in the range of a few millijoules per pulse, in single pulses or in bursts, adjusted to the iris thickness and the response. Burst mode can reduce the number of shots, while focusing slightly behind the iris surface helps control the effect on the lens. Your clinical protocol determines exact values.
The Q-Las covers this range with 0.5–10 mJ, a 4 ns pulse, burst of 1, 2 or 3 pulses, up to 10 Hz Quick-Repetition and a focus shift of 0, 150 or 300 µm posterior. A dual-spot aiming beam, integrated Clear-View filter and optional head-up display help to place and verify each shot. It is offered with PCL5 ZL or SHL slit lamps.
Complications and follow-up
Possible issues include a transient pressure rise, inflammation, bleeding from the iris, closure of the opening, glare or ghost images through the iridotomy, and, rarely, corneal or lens damage. Pressure checks after treatment and follow-up gonioscopy are routine. Patients who report visual phenomena should be examined.
Equipment that delivers consistent pulses and clear optics reduces the number of shots and the chance of misplaced energy. Document the number of pulses, energy, location and result for each eye.
Choosing a YAG laser for iridotomy and capsulotomy
The same Nd:YAG laser performs both iridotomy and posterior capsulotomy, so most clinics buy it for both; see YAG laser capsulotomy and our overview of what a YAG laser is used for. Compare energy range, burst mode, optics, slit lamp and service.
To plan a YAG room or a combined SLT and YAG workstation, contact Beckfinity.
Frequently asked questions
What does a YAG iridotomy do?
It creates a small hole in the peripheral iris so aqueous can flow from behind the iris to the front, relieving pupillary block.
Is a YAG laser iridotomy painful?
Topical anaesthesia is used and the procedure is short; sensation varies by patient. The clinician will explain what to expect.
Which laser is used for iridotomy?
An Nd:YAG laser at 1064 nm, such as the Q-Las, used through a slit lamp with an iridotomy lens.
Can the same laser do capsulotomy?
Yes. The same Nd:YAG platform is used for both procedures.
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