All glaucoma surgery procedures (whether laser or non-laser) are designed to accomplish one of two basic results: decrease the production of intraocular fluid (aqueous humor) or increase the outflow (drainage) of this same fluid. Occasionally, a procedure will accomplish both.
When Is Glaucoma Surgery Needed?
Most cases of glaucoma can be controlled with one or more drugs, but in some cases surgery may be either preferred or more effective. Sometimes, surgery can eliminate the need for glaucoma eye drops. But this is not always the case.
Glaucoma surgery creates a new opening for fluid drainage. Graphic (enhanced) courtesy of National Eye Institute, National Institutes of Health.
Some recent studies indicate that a laser procedure known as selective laser trabeculoplasty (SLT) may be equally as effective as glaucoma eye drops for lowering internal eye pressure. This laser surgery might be considered a primary treatment, particularly for people who find it difficult to comply with the strict, regular schedule needed for administering eye drops.
Another procedure called a trabeculectomy creates an artificial drainage area. This method is used in cases of advanced glaucoma where optic nerve damage has occurred and the IOP continues to soar. A third common option is a shunt, a device that a surgeon implants in your eye to improve fluid drainage.
To increase outflow of internal eye fluid, an ophthalmologist performs laser trabeculoplasty with a laser that creates tiny holes in the filtration angle of the eye, where the cornea and iris meet.
A newer procedure, selective laser trabeculoplasty, creates minimal heat damage to adjacent tissue, which generally means the procedure can be repeated safely.
Laser trabeculoplasties are usually performed as an adjunct to a patient’s ongoing eye drop therapy.
Studies are now investigating whether SLT could be used routinely as a first-line therapy for treatment of open-angle glaucoma and other types of glaucoma, even before eye drops are used.
Trabeculectomy, Trabeculotomy And Goniotomy
Your eye doctor may recommend that a surgical incision be made into the eye’s drainage system to create new channels for more normal flow of fluid. To accomplish this goal, a trabeculectomy involves partial removal of the eye’s drainage system.
A trabeculectomy creates a “controlled” leak of fluid (aqueous humor) from the eye, which percolates under the conjunctiva. A small conjunctival “bleb” (bubble) appears at the junction of the cornea and the sclera(limbus) where this surgically produced valve is made.
A trabeculotomy is the same as a trabeculectomy, except that incisions are made without removal of tissue.
A goniotomy typically is used for infants and small children, when a special lens is needed for viewing the inner eye structures to create openings in the trabecular meshwork to allow drainage of fluids.
Iridotomy And Iridectomy
In an iridotomy, a laser is used to create a hole in the iris to enhance the drainage passages blocked by a portion of the iris.
An iridectomy involves surgically removing a small piece of the iris that will allow a better flow of fluid in eyes with narrow-angle glaucoma.
Shunts And Implants For Glaucoma
Glaucoma shunts and stents are small devices that are surgically inserted into the eye to increase outflow of intraocular fluid and reduce high eye pressure. The devices create an alternative passageway for the aqueous to escape from the eye, bypassing the eye’s damaged or clogged filtration drainage canals.