Roughly 6 percent of patients who undergo a type of surgery called “trabeculectomy” for advanced glaucoma will experience severe loss of central vision, according to a report in the Archives of Ophthalmology for August.

Glaucoma, a leading cause of blindness, is a disorder in which fluid pressure builds up slowly inside the eye causing gradual damage to the optic nerve and impairing vision.

With trabeculectomy, the traditional surgical approach, a pathway is created through a series of incisions, by which the extra fluid in the eye can escape. The fluid is funneled to another part of the eye where it is then absorbed into the bloodstream.

For their research, Dr. Simon K. Law and colleagues, from the University of California, Los Angeles, reviewed the medical charts of 117 patients with severe preoperative visual field defects who underwent trabeculectomy with between June 1998 and October 2005 at one center.

They found that seven patients experienced loss of their central vision following treatment.

Predictors of severe central vision loss included higher intraocular pressures before surgery and complications related to the surgery, the report shows.

SOURCE: Archives of Ophthalmology, August 2007.