CHAPTER 8

Surgical Therapy for Glaucoma

Surgical treatment for glaucoma is usually undertaken when medical therapy is not appropriate, not tolerated, not effective, or not properly utilized by a particular patient, and the glaucoma remains uncontrolled with either documented progressive damage or a high risk of further damage. Surgery is usually the primary approach for both congenital glaucoma and angle-closure glaucoma with pupillary block. In patients with primary open-angle glaucoma (POAG), surgery has traditionally been considered when medical therapy has failed. Caution is especially important because of the potential adverse effects of surgery, including bleb-associated complications, cataracts, and infection. Early studies of trabeculectomy as initial therapy for glaucoma, which were performed before the introduction of some contemporary antiglaucoma medications, suggested that trabeculectomy might offer some advantages—better control of IOP, reduction in the number of patient visits to the physician, and possibly better preservation of the visual field, for example. The results of the Collaborative Initial Glaucoma Treatment Study (CIGTS; see Chapter 4) confirmed that initial surgical therapy achieves better IOP control than does initial medical therapy. However, this finding did not translate to better visual field stabilization in the average subject, because those subjects who received initial surgical treatment had a higher risk of cataract in the long term. In both groups, there was a low incidence of visual field progression. On the other hand, the 9-year follow-up data revealed a considerable subset (approximately 20%) that did show substantial visual field progression. Initial surgery led to less visual field progression than did initial medical therapy in subjects with advanced visual field loss at baseline, whereas subjects with diabetes had more visual field loss over time if treated initially with surgery. Based on the results of this study and on current practice, most clinicians defer incisional surgery for POAG until after initial treatment with medical or laser therapy. Surgical treatment may be accelerated in patients with advanced visual field loss at presentation.

When surgery is indicated, the clinical setting must guide the selection of the appropriate procedure. Each of the many possible procedures is appropriate in specific conditions and clinical situations.

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Musch DC, Gillespie BW, Lichter PR, Niziol LM, Janz NK; CIGTS Study Investigators. Visual field progression in the Collaborative Initial Glaucoma Treatment Study: the impact of treatment and other baseline factors. Ophthalmology. 2009;116(2):200–207.

Musch DC, Gillespie BW, Niziol LM, et al. Cataract extraction in the Collaborative Initial Glaucoma Treatment Study: incidence,