Trabeculoplasty
Selective laser trabeculoplasty (SLT) is a laser treatment used for glaucoma. Laser trabeculoplasty has been performed now for about 30 years and is an effective, accepted way of treating glaucoma. SLT is the same procedure with a newer form of laser. The laser of SLT is known as a "cold laser" because it uses a small fraction of the total energy previously used for laser trabeculoplasty and there is no heat generated. The most common type of glaucoma is associated with elevated eye pressure. Not all individuals with elevated pressure develop glaucoma and conversely not all individuals with glaucoma have elevated pressure. All glaucoma treatments have a common aim of lowering fluid pressure inside the eye. Studies have shown that lowering the pressure of the eye lessens the chance for glaucoma progression. The ideal pressure for an individual is different for everybody, however one generally aims for at least a 30% reduction from pretreatment pressure. Traditionally eye drops have been the first line of treatment in glaucoma. If drops are ineffective or people are unable to tolerate the side effects of drops the next step would be laser trabeculoplasty. Following laser trabeculoplasty and drops, if pressure requires further lowering, then filtering surgery would be the final step. Nowadays laser trabeculoplasty is being offered when an individual is already on one or two types of eye drop and in some situations even as a first measure.
How does laser trabeculoplasty work?
One can think of the inside of the eye like a sink with an area that produces fluid and a drain where fluid exits the eye. Elevated pressure in the eye is caused by resistance to fluid flow out the drain. As the resistance increases so does one's eye pressure. Generally drain resistance increases with age.
The "drain" of the eye is known as the trabecular meshwork. This is located where the cornea meets the iris and runs for 360 degrees. SLT is performed when an individual is in a chair using a contact lens. The treatment takes about 5 minutes for both eyes and is painless. It takes about six weeks to six months to have the full effect of the treatment. Generally we do one-half of the total amount of treatment at one sitting and await to see the response. If the second half of the treatment is required, generally we will know between three to six months after the initial treatment. The mechanism at work here is thought to be the activation of cells in the trabecular meshwork which clean up debris and lower the resistance to fluid outflow and pressure in the eye. 80% of people have a good reduction of pressure, 20% have no change in pressure. In 1 in 1000 individuals, the pressure goes up and consequently a further line of treatment is required such as drops or even surgery.
After the treatment
Use your regular eye drops after the laser treatment unless instructed otherwise. There will be two-week, six-week, and three-month follow up visits for pressure checks. You will have a drop to use four times a day for three days after the laser treatment which is separate from your regular eye drops.
SLT is performed while an individual is in a chair using a contact lens. If the second half of the treatment is required, generally we will know between three to six months after the initial treatment. The mechanism is thought to be by activation of cells in the trabecular meshwork, which clean up debris and lower the resistance to fluid outflow and pressure in the eye.
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