Glaucoma Laser

A selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT) are both very similar laser procedures to reduce the eye’s pressure. This is done in the office by placing a special contact lens on the eye. The laser is then focused through this lens to the angle of eye (trabecular meshwork). The laser helps improve aqueous outflow which in turn helps reduce the eye’s pressure.

Goniotomy

A Goniotomy is a Minimally Invasive Glaucoma Surgery (MIGS) which can lower intraocular pressure by improving the outflow dynamics of the eye. It was originally used to treat Glaucoma in children, but has been adapted to treat mild to severe Glaucoma in adults.

A Goniotomy opens the eye’s natural fluid drainage pathway by removing part of the trabecular meshwork. By opening the eye’s natural fluid drainage pathway, the intraocular eye pressure should decrease. There is no need for a stenting device with this procedure. A Goniotomy can be performed with or without Cataract Surgery. The post-operative care and follow-up is similar to Cataract Surgery.

The most common instrument to perform a Goniotomy is a KDB Glide. Below is a diagram demonstrating the removal of the trabecular meshwork.

What is a Trabeculectomy?

A trabeculectomy is a glaucoma surgery that creates a small hole in the anterior chamber of the eye to allow drainage of the aqueous fluid toward the outside. Trabeculectomy surgery starts with making an incision through the conjunctiva. Underneath the scleral flap, a surgeon cuts a small hole into the anterior chamber, which allows the drainage of aqueous fluid through the scleral flap and into the sub-conjunctival space. An iridectomy (hole in the iris) is performed at this point to allow the scleral opening to stay open without being blocked by the iris tissue. The scleral flap is then tied down with stitches, that are loose enough to allow continuous drainage of the aqueous fluid. Finally, the overlying conjunctival tissue is closed with stitches to allow formation of a bleb or an elevation of conjunctival tissue formed by the aqueous fluid, which is being filtered out of the scleral flap (trapdoor) underneath. The filtering bleb is usually located in the superior aspect of the eye and covered by the upper lid.  It is not readily noticeable by a casual observer. The aqueous fluid from the filtering bleb is then slowly absorbed by the conjunctival and episcleral (on the surface of the sclera) blood vessels and drain into the orbital venous system.

What is a Seton Implant?

The seton implant is similar to a trabeculectomy, in that the goal is to decrease the eye’s pressure, by creating a pathway for the fluid inside the eye (aqueous fluid) to drain to the outside.  A tube is inserted into the anterior chamber so the aqueous fluid can drain into the seton implant and out of the anterior chamber of the eye.   The implant is sutured into a conjunctival pocket and the aqueous is absorbed naturally.

The diagram below shows the step-by-step insertion of a Ahmed Valve ® which is one of the most common seton implants.