WHEN SHOULD I PERFORM INCISIONAL GLAUCOMA SURGERY? WHICH PROCEDURE SHOULD I CHOOSE?

The decision to perform incisional glaucoma surgery is not an easy one. Surgery has traditionally been reserved for patients who are progressing or are deemed likely to progress despite maximally tolerated medical and/or laser therapy. It is at this point that the risk of continuing to observe outweighs the risks of performing surgery. Doctors, as well as patients, are often reluctant to go to the operating room early during the course of treatment despite the results of landmark studies such as the Collaborative Initial Glaucoma Treatment Study (CIGTS), which have challenged the traditional therapeutic approach. The CIGTS study found that lowering intraocular pressure (IOP) with initial filtering surgery is as effective as medical therapy for slowing progression of visual field loss. In fact, patients with more advanced visual field loss (mean deviation worse than -10 dB) actually did better with initial surgery compared with those who were initially treated with medication. ^{1, 2, 3 and 4} Surgically treated patients likely benefit from less diurnal IOP fluctuation, lower peak pressures, and a lower mean IOP. In the Moorfields Primary Treatment Trial (PTT), patients who underwent trabeculectomy had a mean IOP of 14.5 mm Hg at 5 years compared with 18.5 mm Hg for those patients treated with either medication or laser therapy. In addition, there was a higher rate of success for the surgical group that was sustained throughout the 5 years of follow-up. ^5,6 Neither the Moorfields PTT nor CIGTS studies found any significant difference in the mean loss of visual acuity between the medical treatment and surgery groups.