PurposeTo compare the long-term effect of treating newly diagnosed open-angle glaucoma with standard medical treatment versus filtration surgery.
BackgroundRecent studies have challenged the conventional wisdom of treating all newly diagnosed open-angle glaucoma (OAG) with eyedrops; rather, these studies suggest that more effective control of glaucomatous damage can be obtained by immediate filtration surgery. In addition, increased attention to the impact of therapy on health-related quality of life has added another consideration in deciding upon appropriate treatment of such patients.
DescriptionThe Collaborative Initial Glaucoma Treatment Study (CIGTS), a randomized, controlled clinical trial, is being conducted to determine whether patients with newly diagnosed OAG are best managed by the conventional approach of topical pharmacologic agents or by immediate filtration surgery. Eligible patients were randomized to receive either a stepped medication treatment regimen or filtration surgery to control their OAG. Sample size requirements indicated that 300 patients were needed for each treatment approach; a total of 607 patients were ultimately recruited for the CIGTS.
Patients randomized to the medication treatment arm are receiving a stepped regimen of topical medications, beginning with a single agent (typically a beta blocker), with additional medications added upon documented lack of intraocular pressure control or evidence of progressive visual field loss. If medications fail to control the patient's OAG, a series of treatment steps begin with argon laser trabeculoplasty and conclude with trabeculectomy.
In the surgical treatment arm, patients underwent immediate trabeculectomy and, with documented failure, proceed to argon laser trabeculectomy, then conclude with medications. Patients, rather than eyes, are randomized to the two treatment arms; if both eyes are eligible for treatment, the treatment course for both eyes is the same and was determined in the randomization.
Following randomization, participating community ophthalmologists affiliated with the study have been allowed to manage the medical and surgical care of study patients. However, all patients are seen at the Clinical Centers for standardized followup examinations at 3 and 6 months after treatment and every 6 months thereafter; in addition, patients randomized to the surgical arm will receive, at a minimum, postsurgical followup at 1 day, 1 week, and 1 month. At the Clinical Center visits, examination of the eye(s) includes evaluation of visual acuity, visual field, and intraocular pressure. The results of these tests determine whether treatment should be changed. In addition, before and at regular intervals after treatment, patients are being interviewed by telephone to assess their health-related quality of life. A questionnaire that includes the Sickness Impact Profile, Visual Activities Questionnaire, and other components is being used.
Patient EligibilityPatients ranged in age from 25 to 75 with an intraocular pressure of 20 mm Hg or greater and evidence of optic nerve damage and/or visual field loss in one or both eyes. The ocular findings must exclude causes of glaucoma other than primary open-angle glaucoma, pigmentary glaucoma, or pseudoexfoliation glaucoma.
ResultsInterim results including follow-up as long as 5 years were reported in November, 2001. Both treatment groups had substantial and sustained reduction in IOP from baseline with the surgical group running IOPs about 2-3 points lower than the medical group. The surgical group had more visual field loss and more visual acuity loss in the first 3 years of the Study, but these differences largely disappeared in years 4 and 5 of follow-up. The surgery group had more cataract extractions than the medical group. Quality of life results indicated that both groups were satisfied with their treatment. While the surgery group reported more local eye symptoms such as feeling something in the eye, most such symptoms were not sustained beyond the first 2-3 years of follow-up. The medical group reported a variety of systemic symptoms that were not consistent over time, but were clearly different from the symptoms reported by the surgical group. Based on these interim follow-up data, the investigators do not recommend changes to current approaches to managing newly diagnosed open-angle glaucoma patients. Longer follow-up is needed before specific treatment recommendations can be made in a chronic disease like glaucoma.