Angle Recession Glaucoma (cont.)

Surgery

In angle recession glaucoma, surgery is recommended when the maximum amount of medicine has been tried and failed to reduce IOP and when the risk of vision loss outweighs the risk of surgery. Either laser surgery or conventional incisional surgery in an operating room may be needed.
 
Although favorable results have been reported for surgical intervention of angle recession glaucoma, success rates are lower when compared to other forms of glaucoma. Your eye doctor will discuss the risks and benefits of each procedure with you.

Laser surgery

Argon laser trabeculoplasty

During a trabeculoplasty, the ophthalmologist uses an argon laser beam to place small spots (burns) on the trabecular meshwork, which further open the spaces in the trabecular meshwork, allowing the fluid (aqueous humor) to flow better out of the eye. In effect, this should lower IOP.

• Argon laser trabeculoplasty is successful in the short term, but the procedure is not as effective for the long term, particularly in eyes with angle recession involving more than 180° of the iris.
  
  
• In eyes with angle recession involving less than 180° of the iris, argon laser trabeculoplasty is useful if applied only to the part of the angle not involved in angle recession.

Other laser procedures

Laser procedures other than an argon laser trabeculoplasty may be performed. Some recent procedures that have shown promise (but are not discussed herein) include transscleral krypton laser cyclophotocoagulation, transpupillary argon laser cyclophotocoagulation, and endoscopic cyclophotocoagulation.

Conventional incisional surgery

If medicine and laser surgery have failed to adequately control IOP, then conventional incisional surgery (also known as filtering surgery) may be performed. The most common filtering surgery is trabeculectomy.

Trabeculectomy

During trabeculectomy, the ophthalmologist creates an alternate pathway (or drainage channel) in the eye to increase the passage of fluid (aqueous humor) from the eye. By constructing a new drainage channel, aqueous humor is able to flow better from the anterior chamber into a bleb (a space created for drainage of aqueous humor) below the conjunctiva. As a result, IOP is lowered.

Medicines, called antimetabolites, are sometimes used in conjunction with trabeculectomy. They help reduce scarring and increase the chance of IOP being lowered.

Although effective, trabeculectomy for angle recession glaucoma has a lower success rate when compared to POAG. Trabeculectomy in eyes with angle recession is associated with less IOP reduction after surgery, greater bleb fibrosis (scarring), higher rate of bleb failure, and greater dependence on glaucoma medications after surgery.

Drainage implant surgery

Drainage implant surgery is generally performed after one or more attempts at trabeculectomy have failed.

In drainage implant surgery, the ophthalmologist places a tube in the anterior chamber to shunt the aqueous humor. Different types of implants can be used, but most function by allowing better drainage of the aqueous humor from the anterior chamber, thereby lowering IOP.

Although beneficial, drainage implant surgery may be less successful in angle recession glaucoma than in other types of glaucoma. In angle recession glaucoma caused by a traumatic event, one study reported better results using trabeculectomy with antimetabolites over drainage implant surgery.