An argon laser trabeculoplasty, or ALT, is a type of glaucoma surgery. Glaucoma is the name given to a group of disorders which damage the eye's optic nerve, and which carry a risk of blindness if left untreated. Argon laser trabeculoplasty is used to treat a form of glaucoma known as open angle glaucoma, where the pressure inside the eye, called the intraocular pressure, is too high. The ALT procedure reverses this pressure increase by using a laser to burn holes in the drainage area of the eye, allowing fluid to escape.
Most often, glaucoma laser treatment is only considered for patients with open angle glaucoma after medication has failed to work. Open angle glaucoma is associated with abnormalities in the drainage of fluid from the eye. All around the edge of the colored part of the eye, or iris, lies a structure known as the trabecular meshwork. The trabecular meshwork normally acts like a sieve, allowing fluid to drain out of the eyeball, but in open angle glaucoma the meshwork is partly blocked. As fluid can no longer pass out of the eye so easily, pressure inside builds up over time, damaging the optic nerve.
At first, drugs can be given in the form of eye drops, in order to lower the intraocular pressure. If different medications have been tried and failed to stop the progression of the glaucoma, surgery such as argon laser trabeculoplasty may be carried out. The procedure takes place using local anesthetic, with the patient awake and sitting up in a chair, and lasts for around ten to 20 minutes.
During the argon laser trabeculoplasty, the person's forehead and chin are supported by a machine called a slit lamp, a type of microscope used to guide the laser. Eye drops are used to shrink the pupil and numb the eye, and a contact lens is inserted. The lens helps provide a clear view of the trabecular meshwork, and also helps stop the eye from moving. Finally, the lens is shifted and the laser is used to make a number of minute burns in the trabecular meshwork, opening up channels through which fluid can drain.
One or two hours following the argon laser trabeculoplasty, the pressure in the eye will be checked. The patient may be given eye drops to use for a couple of weeks to reduce any inflammation. Vision may appear blurry at first, but this normally resolves within days. It is not possible to know in advance whether the treatment will work, so for some people the disadvantage of the procedure will be that their eye pressure has not lowered, and the progression of their glaucoma continues.