Yag PI laser treatment for glaucoma is the name of a laser treatment used to treat patients with glaucoma and is one of the various laser procedures. Some refer to this as laser surgery for glaucoma, but that would be a misnomer. Laser peripheral iridotomy or Yag Pi's full form is Nd: YAG (neodymium-doped yttrium aluminium garnet) Peripheral laser iridotomy. Nd Yag is the name of the crystal used in the laser machine to treat glaucoma.
Glaucoma is a group of eye diseases with increased eye pressure, which causes damage to the optic nerve and the retina. There are various types of glaucoma.
Acute narrow-angle glaucoma, also called angle-closure glaucoma or narrow-angle glaucoma, is one of the two basic categories of glaucoma. The other category is open-angle glaucoma. The first form of glaucoma mentioned here requires laser peripheral iridotomy.
First, let us try and explain the structure of the eye. The ciliary process makes the fluid that occupies the front part of the eye. These ciliary processes are attached to the ciliary body. And this ciliary body is present behind the iris, which is the brown part of your eye. Acute narrow-angle glaucoma occurs in patients with a shallow space between the cornea at the front of the eye and the coloured iris behind the cornea. This space is known as the anterior chamber.
As the eye ages, the natural lens behind the pupil grows thicker. Also, as the eye ages, the pupil becomes smaller, restricting fluid flow to the drainage site. The drainage site is between the back part of the cornea and the front part of the iris. It's also called the angle. The actual name of the structure that drains the fluid from the eye is called the trabecular meshwork.
If the pupil becomes smaller and the lens thicker, a situation may arise where the round pupil presses against the lens just behind it. If this happens, fluid flow from behind the iris through the pupil to the front of the iris stops. The fluid can build up behind the iris, pushing the iris forward like a sail of a boat. This ballooning of the iris can block the channel (angle) that allows aqueous fluid to drain. Because of this closed-angle, the fluid outflow from the eye stops. A rapid rise in intraocular pressure can occur.
This rapid rise in pressure is known as acute angle-closure glaucoma and can significantly damage the optic nerve if left untreated, resulting in irreversible vision loss. Symptoms of acute angle-closure glaucoma are blurred vision, redness, and severe pain.
We examine the eye pressure as a routine check-up in all patients who come in for an eye examination at Eye Solutions, Mumbai, India. Of course, we also do a detailed eye examination, including a vision check and glass power check. When we find raised eye pressure, we first assess the angle of the eye. If this angle is narrow or the glaucoma specialist feels that the narrow-angle may be blocking the path of eye fluid on its way out, he may consider the Yag PI laser.
Sometimes we see narrow-angle suspects where the angle appears narrow, and pressure is borderline. There may also be a positive family history of glaucoma eye disease. In these patients, too, Yag laser treatment may be done. These patients are known as primary angle-closure suspects. In other words, having a narrow-angle is a risk factor for developing acute angle-closure glaucoma.
As mentioned previously, Yag PI's full form is Yag Peripheral Iridotomy. This laser makes a new opening or hole in the iris to allow the aqueous fluid to move more easily to the drainage site. The iris is the coloured part of the eye. Once the aqueous starts flowing more efficiently, the eye pressure decreases. One can read more about glaucoma here, but you should know that the damage to the retinal nerve fibre layer reduces once the pressure decreases. In other words, the optic nerve head stops getting damaged.
Since the opening is at the very edge of the iris, we call it "Peripheral iridotomy". We perform this laser treatment in the doctor's office. It is generally performed on both eyes because the risk of developing the condition is high.
We call the patient 30 min before the Yag PI laser scheduled time. Once the patient arrives, we start putting Pilocarpine eye drops in one or both eyes. These drops constrict the pupil or make it smaller, stretching the peripheral iris so that the procedure is easier and more effective. These drops may cause a feeling of heaviness or eyestrain. Fortunately, this is only temporary and subsides over the next few hours.
After that, the patient sits in front of the laser machine, placing their chin on the chin rest. Anaesthetic drops numb the eye, and then a contact lens is placed on the eye's surface. This laser procedure may sound scary but because of the numbing drop,s this step does not hurt.
Then the doctor looks for a spot on the iris which is thin. Once the site is found, the lens is rotated to ensure it is in focus, and we fire the laser beam. Usually, Your doctor may need 2-4 shots. When your doctor sees a burst of iris pigment flow into the Anterior chamber, they know it's done. Eye doctors and glaucoma specialists call this pigment dispersion into the anterior chamber.
The entire procedure takes 5 to 7 min for each eye and is an outpatient and a stand-alone procedure.
After the laser treatment, we prescribe certain eye drops. These eye drops are anti-inflammatory and reduce inflammation due to the laser. As explained earlier, your eye doctor has caused an injury to your eye with that laser, and the body will react to it. The drops will help in reducing that reaction.
Sometimes, the vision may become blurred because of minimal bleeding. There is nothing to worry about even if this happens as the blood clears up in a week, and vision should return to normal.
Once the iris opening is made, it doesn't need to remain open forever. The reason for this is that the body considers this as an injury. Like for any other injury, the body tries and repairs this injury. The repairing may happen by healing the iris tissue and closing the YAG laser-created opening. There is a 20-30 % chance of the opening-closing. If that happens, the laser may have to be repeated.
The pressure doesn't need to reduce to the level that your treating eye doctor wants after the laser. So even though the pressure has gone down, it has not reached a level that your doctor wants. In this situation, your glaucoma specialist may prescribe certain eye drops that would help in reducing the pressure further, which is medical management of glaucoma or eye drops to lower the pressure.
Suppose the pressure does not reduce to the target level with glaucoma eye drops. In that case, your doctor may suggest you get a glaucoma filtering surgery, also known as trabeculectomy, and it is one type of glaucoma surgery.
There is also another option that your doctor may consider if the pressure does not drop to the desired levels. If you also have a cataract, your doctor may consider performing cataract surgery even if the cataract is not very advanced. Usually, after cataract surgery, the pressure reduces by a bit, which may help reach the eye pressure target. You can read more about cataract surgery.