Central vision loss a problem following trabeculectomy?

In patients with advanced visual field loss undergoing trabeculectomy with mitomycin C, there is a risk of severe loss of central vision, according to the results of a study published in the August issue of Archives of Ophthalmology.

A retrospective review was conducted of the records of patients with severe preoperative visual field defects undergoing trabeculectomy between June 1998 and October 2005. Severe loss of central vision was defined as visual acuity (VA) of 20/200 or less in the affected eye, counting fingers or less if preoperative VA was less than 20/200, or a greater than four line reduction in Snellen VA.

Of 117 subjects, central vision loss occurred in seven (6%), due to hypotony maculopathy (three cases), uncontrolled elevated intraocular pressure (IOP) (two cases), posterior subcapsular cataract increase (one case) and inflammatory reaction (one case). A significant reduction in VA was noted following surgery, from -0.31 to -0.39 (logMAR, p=0.01). The patients who did suffer a severe loss of central vision, had significantly higher mean ±SD preoperative IOPs and higher rates of surgical complications compared with those who did not.

It would seem that there is a risk of severe central vision loss after trabeculectomy in patients with advanced visual field loss.