SLT - Selective Laser Trabeculoplasty
Introduction
If you have glaucoma, lowering the eye pressure is the main method of preventing glaucoma from damaging your vision. The pressure can be lowered with three methods: medications, laser, or surgery. Glaucoma surgery is reserved for cases where medications or laser treatments fail to bring the pressure down to an acceptable level. Medications act by either decreasing the amount of fluid entering the eye, or helping the fluid leave the eye more easily. Medications are very useful but can have side effects, and require diligence in putting the drops in on a daily basis. The SLT laser can lower the eye pressure without the need for drops, or can decrease the number of drops needed to reach an acceptable pressure. The SLT lowers the pressure by helping the drain of the eye to function more efficiently.
Anatomy
The eye is filled with a clear fluid, called the aqueous, which provides nutrients and helps to maintain the round shape of the eyeball. A specialized tissue (ciliary body) creates a constant supply of the fluid; and another area in the eye (trabecular meshwork) acts as a drain. The fluid constantly flows throughout the eye – from the ciliary body it travels around the lens, through the pupil, and then leaves the eye through the trabecular meshwork located next to the outer edge of your iris. When the drain of the eye gets blocked, the eye pressure slowly increases. High eye pressure pushes against the optic nerve and leads to nerve injury.
How does SLT work?
The SLT laser flashes a short, powerful, burst of light at the trabecular meshwork (drain). The heat from the laser light is absorbed into pigment-containing cells and creates microscopic damage to these cells. It is believed that this small amount of damage signals the eye to repair the drain. Specialized chemicals and cells repair the drainage tissue, which ultimately leads to improved function of the drain and lower eye pressure.
Are there any alternatives to having the laser done?
Continued use of medications or accepting a higher pressure and possible ongoing glaucoma damage are the alternatives.
Are there side effects of the laser?
Because the laser is specifically directed at the drain of the eye it would be unusual to develop any complications from the laser. In rare cases the eye pressure may increase temporarily, or the eye may develop inflammation that causes the eye to be red and irritated.
Will the laser affect my vision?
It would be very rare for the laser to make your vision better or worse, since it does not work on any area of the eye other than the drain. Increased inflammation or swelling in the cornea or retina could cause blurring of the vision, but are very rare.
What am I to expect on the day of surgery?
After arrival your vision and eye pressure will be checked. Your doctor will review the procedure with you and answer any question that you may have. You will need to sign a consent form before the procedure. You will be given several drops to prepare the eye for the laser. The laser surgery takes 10-15 minutes. Most people feel no discomfort, but you may feel a slight burning sensation. When the laser is complete you will be given additional drops to prevent the pressure from increasing. You will then need to wait in the office for 30-60 minutes for a pressure check. If the pressure is fine you will be able to leave. The vision may be dark and blurry for 2-3 hours after the surgery because of the bright lights and lenses used. Because of this you should have someone with you to drive you home. This is especially true if you have poor vision in your eye that did not have the laser or if both eyes are treated. In most cases, a follow-up appointment will be arranged for 2-4 weeks after the laser to see how well the treatment lowered the eye pressure.
Are there symptoms to watch out for after the laser?
You may experience a little irritation or ache in the eye for a few days after the laser. Tylenol is usually all you may need to help with any discomfort. If you develop significant redness, light sensitivity, blurred vision, headache, halos around lights, or nausea you should contact your doctor immediately. These symptoms could be from increased inflammation or high pressure in the eye.
Does the laser work in everyone?
Most people get a significant decrease in the eye pressure from the laser treatment. However, due to normal biological variability and the amount of pre-existing malfunction of the drain, about 20% of treatments lower the pressure less than expected. If your eye pressure decreases less than expected a second treatment can be considered or topical eye drops can be used.
How much will the laser cost me?
This is an important question and varies greatly depending on your co-pay and deductible amounts. The charge for the laser is less than half of what a year’s worth of glaucoma drops would cost. Your doctor should always check with your insurance before the procedure to make sure it is a covered benefit and to determine what your out-of-pocket expense will be.
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