Glaucoma Laser Surgery

Laser surgeries have become important in the treatment of glaucoma. There are several types of glaucoma laser surgery and the type of surgery selected will depend on the form of glaucoma and how severe it is. Lasers produce a focused beam of light that can make a very small burn or opening in the eye tissue, depending on the strength of the light beam. Laser surgeries are typically performed in an outpatient setting in a doctor's office or in a hospital clinic.

The following are the most common laser surgeries to treat glaucoma.

Argon Laser Trabeculoplasty (ALT):

Argon Laser Trabeculoplasty (ALT) is used for the treatment of primary open-angle glaucoma (POAG).

To increase the outflow of internal eye fluid, an ophthalmologist performs ALT with a laser that creates tiny holes in the filtration angle of the eye, where the cornea and iris meet. The laser beam in effect opens the fluid channels of the eye, helping the drainage system work better. In many cases, medication will still be needed.

Usually, half the fluid channels are treated first. If necessary, the other fluid channels can be treated in a separate session at another time. This method prevents over-correction and lowers the risk of increased pressure following surgery.

ALT has successfully lowered eye pressure in up to 75% of patients treated.

Selective Laser Trabeculoplasty (SLT)

Selective Laser Trabeculoplasty (SLT) is used for the treatment of primary open-angle glaucoma (POAG).

SLT uses a laser that works at very low levels. It treats specific cells "selectively," leaving untreated portions of the trabecular meshwork intact. For this reason, SLT may be safely repeated. The heat from the laser light is absorbed into pigment-containing cells and creates microscopic damage to these cells that in turn activates repair of the drain.

SLT may be used as a first-line glaucoma treatment, an adjunct treatment or as an alternative for those who have been treated unsuccessfully with ALT or pressure-lowering eye drops.

SLT has successfully lowered eye pressure in over 90% of patients treated, when used as primary therapy.

Micropulse Laser Trabeculoplasty (MLT)

Micropulse laser trabeculoplasty (MLT) provides the same pressure-lowering effects as argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT) with less energy and inflammation than the other procedures. MLT uses a specific diode laser (IQ 810, Iridex) with a much longer pulse length than SLT, but the temperature rises slowly, because laser energy is delivered in short microbursts over an extended period of time (milliseconds for MLT versus nanoseconds for SLT). The micropulse helps to minimize the spikes in eye pressure that can sometimes occur after a laser procedure.

Laser Peripheral Iridotomy (LPI)

Laser Peripheral Iridotomy (LPI) is used for the treatment of narrow angles and narrow-angle glaucoma. Narrow-angle glaucoma occurs when the angle between the iris and the cornea in the eye is too small. This causes the iris to block fluid drainage, increasing inner eye pressure. LPI employs a laser that creates a small hole in the iris, producing an alternate pathway for the fluid to reach the drainage area of the eye.

Laser Cyclophotocoagulation

Laser Cyclophotocoagulation is a surgical alternative to filtering microsurgery that is typically used later in the treatment algorithm, especially when medications can’t be tolerated or are not working well. In cyclophotocoagulation, several different types of lasers can be used to cause destruction of the ciliary body and therefore decrease the amount of fluid produced in the eye, thus lowering the eye pressure. The procedure can be done from outside the eye as an in-office procedure, or inside the eye in a surgery center, and may need to be repeated in order to permanently control glaucoma.

Canaloplasty

Canaloplasty is a nonpenetrating procedure utilizing microcatheter technology. In this procedure, the ophthalmologist first makes a small incision in the eye and then inserts the canaloplasty microcatheter into the eye's drainage system canal. The doctor then uses the microcatheter to circle the canal and enlarge it to help the aqueous fluid to drain. The microcatheter is then removed and a suture is placed within the canal to keep it open. This restores the eye's drainage system to permanently lower the pressure in the eye.

Trabectome Surgery
Trabectome® is a minimally invasive procedure designed to improve fluid drainage from the eye to balance intraocular pressure in patients with open-angle glaucoma. The surgery is performed through a small incision and does not require leaving a permanent hole in the eye wall or creation of an external filtering bleb (fluid collection on the outside of the eye) or an implant. The pulse from an electrosurgical handpiece is used to open access to the eye's drainage system. Trabectome is an out-patient surgery that allows the patient to go home the same day.

The Ex-Press Mini Shunt
The Ex-Press Mini Shunt is a very small stainless steel device used to augment conventional trabeculectomy surgery. The device helps to standardize the operation and may also reduce the chances of the eye pressure getting too low in the immediate post-operative period. The Ex-Press Mini Shunt allows precise control of the amount of fluid allowed to flow out of the eye, which helps to maintain a healthy level of internal pressure. It is sometimes used after a standard trabeculectomy has failed, to increase the chances of a successful outcome.

Long-term benefits of glaucoma laser surgery
Glaucoma laser surgeries help to lower the intraocular pressure (IOP) in the eye. The length of time the IOP remains lower depends on the type of laser surgery, the type of glaucoma, age, race, and many other factors. Some people may need the surgery repeated to better control the pressure.

Medication following laser surgery
In most cases, medications are still necessary to control and maintain eye pressure. However, surgery may lessen the amount of medication needed.

Recovery time
Glaucoma surgery is usually performed in an ophthalmology office or eye clinic. Before the surgery, the eye is typically numbed with medicine. The eye may be a bit irritated and the vision slightly blurry after the surgery. Patients should arrange a ride home after surgery.

In general, patients can resume normal daily activities the next day after glaucoma laser surgery.

Risks of Laser Surgery
As with any type of surgery, glaucoma laser surgery can carry some risks. Some people experience a short-term increase in their intraocular pressure (IOP) soon after surgery. In others who require YAG CP (Cyclophotocoagulation) surgery, there is a risk of the IOP dropping too low to maintain the eye’s normal metabolism and shape. The use of anti-glaucoma medication before and after surgery can help to reduce this risk. There is a small risk of developing cataracts after some types of laser surgery for glaucoma. However, the potential benefits of the surgery usually outweigh any risks.

If you liked this article, visit www.glaucoma.org for more educational articles like this. The Glaucoma Research Foundation offers patient education booklets and brochures for your patients. Please click here to order bulk copies for your office or practice.