NEI Clinical Studies
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Advanced Glaucoma Intervention Study (AGIS)
To assess the long-range outcomes of sequences of interventions involving trabeculectomy and argon laser trabeculoplasty in eyes that have failed initial medical treatment for glaucoma.
In advanced glaucoma, medication alone no longer reduces intraocular pressure adequately, and the eye has field defects. Before 1980, some type of filtering surgery, such as trabeculectomy, was the usual method of intervention. Since then, laser trabeculoplasty has become a popular alternative. Sometimes the first intervention chosen succeeds in controlling pressure for many years; at other times, the success lasts only a few weeks or months. Because success is limited, some patients, over time, need to undergo a sequence of surgical interventions. Little is known about which sequence gives the best long-range outcome.
The Advanced Glaucoma Intervention Study (AGIS) is designed to provide a comprehensive assessment of the long-range outcomes of medical and surgical management in advanced glaucoma. The study uses visual function status to compare two intervention sequences in managing the disease.
Eligible eyes are randomly assigned to one of two intervention sequences: (1) trabeculectomy, followed by argon laser trabeculoplasty (ALT) should trabeculectomy fail, followed by a second trabeculectomy should ALT fail; or (2) ALT, followed by trabeculectomy should ALT fail, followed by another trabeculectomy should the first trabeculectomy fail. Antifibrotic agents may be used as an adjunct to trabeculectomy, but only in eyes with a previous history of invasive surgery. Eyes that fail the entire assigned sequence of interventions are managed at the discretion of the AGIS physician in collaboration with the patient.
Interventions are supplemented with medical treatment as needed. A total of 789 eyes with advanced glaucoma have been enrolled. All patients are being followed under a standardized protocol for a minimum of 5 years to determine degree of visual function loss, failure rates of interventions, rates of complications, and need for supplemental therapy.
After the initial intervention, followup examinations are scheduled at 1 week, 4 weeks, 3 months, 6 months, and every 6 months thereafter. After second and third interventions, followup examinations are scheduled at 1 and 4 weeks. Additional visits are scheduled as necessary for the management of the disease.
The primary outcome variable in AGIS is average percent of eyes with decrease of vision, where decrease of vision is a substantial decline of either visual field or visual acuity attributable to the effect of glaucoma. Secondary outcome variables include sustained decrease of vision, failure of interventions, number of prescribed glaucoma medications, and level of intraocular pressure. An ancillary study is assessing filtering bleb encapsulation.
Men and women between the ages of 35 and 80 with open-angle glaucoma that was not successfully controlled by medication were eligible for enrollment.
Patient Recruitment Status
Completed. Recruitment began in April 1988 and closed in November 1992 after 789 eyes of 591 patients were enrolled.
Current Status of Study
Ongoing. Followup of patients continues.
After seven years of follow-up on these patients enrolled in the AGIS, results revealed that blacks and whites differed in the way they benefited from the two treatment programs. The vision in eyes of black patients with advanced glaucoma tended to be better preserved in the program that started with the laser surgery. From initial treatment through seven years of follow-up, the average percent of eyes in black patients with decrease of vision was 28 percent in the program starting with laser surgery, as compared with 37 percent in the program starting with a trabeculectomy.
Through the first four years, the vision in eyes of white patients with advanced glaucoma tended to be better preserved in the program starting with laser surgery. Thereafter, however, the reverse was true; seven years after the initial treatment, the average percent of eyes in white patients with decrease of vision was 31 percent in the program starting with a trabeculectomy, as compared with 35 percent in the program starting with laser surgery.
Based on the study results, it is recommended that black patients with advanced glaucoma begin a treatment program that starts with laser surgery, which is consistent with current medical practice. In contrast, white patients with advanced glaucoma who have no life-threatening health problems should begin a treatment program that starts with trabeculectomy. This recommendation is inconsistent with current medical practice."
Because glaucoma is a life-long disease, long-term information is important. The AGIS patients will continue to be followed for up to four more years.
The Advanced Glaucoma Intervention Study Investigators: The Advanced Glaucoma Intervention Study (AGIS) 8: Risk of cataract formation after trabeculectomy. Arch Ophthalmol 119: 1771-1780, 2001.
Gaasterland DE, Blackwell B, Dally LG, Caprioli J, Katz LJ, Ederer F, and The AGIS Investigators: The Advanced Glaucoma Intervention Study (AGIS): 10. Variability among academic glaucoma subspecialists in assessing optic disc notching. none 99: 177-185, 2001.
The AGIS Investigators: The Advanced Glaucoma Intervention Study (AGIS): 9. Comparison of glaucoma outcomes in black and white patients within treatment groups. Am J Ophthalmol 132: 311-320, 2001.
The AGIS Investigators: The Advanced Glaucoma Intervention Study (AGIS): 6. Effect of cataract on visual field and visual acuity. Arch Ophthalmol 118: 1639-1652, 2000.
The AGIS Investigators: The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration. Am J Ophthalmol 130: 429-440, 2000.
Schwartz AL, Van Veldhuisen PC, Gaasterland DE, Ederer F, Sullivan EK, Cyrlin MN, and The AGIS Investigators: The Advanced Glaucoma Intervention Study (AGIS): 5. Encapsulated bleb after initial trabeculectomy. Am J Ophthalmol 127: 8-19, 1999.
AGIS Investigators: Advanced Glaucoma Intervention Study (AGIS): 3. Baseline characteristics of black and white patients. Ophthalmology 105: 1137-1145, 1998.
AGIS Investigators: Advanced Glaucoma Intervention Study (AGIS): 4. Comparison of treatment outcomes within race: 7 yr results. Ophthalmology 105: 1146-1164, 1998.
The Advanced Glaucoma Intervention Study (AGIS) Data Management Handbook. Springfield, Virginia. National Technical Information Service, Document, No. PB96-137120, 1996.
The Advanced Glaucoma Intervention Study Investigators: The Advanced Glaucoma Intervention Study (AGIS): 1. Study design and methods, and baseline characteristics of study patients. Controlled Clinical Trials 15(4): 299-325, 1994.
The Advanced Glaucoma Intervention Study Investigators: The Advanced Glaucoma Intervention Study. 2. Visual field test scoring and reliability. Ophthalmology 101: 1445-1455, 1994.
The Advanced Glaucoma Intervention Study (AGIS) Manual of Operations. Springfield, Virginia. National Technical Information Service, No. PB93-220192, 1993.
Douglas Gaasterland, M.D.
University Ophthalmic Consultants of
Washington 4910 Massachusetts Avenue,
Suite 210 Washington, DC 20016 USA
Telephone: (202) 686-6800
Fred Ederer, M.A., F.A.C.E.
The EMMES Corporation
11325 Seven Locks Road, Suite 214
Potomac, MD 20854
Telephone: (301) 299-8655
Maryann Redford, D.D.S., M.P.H.
National Eye Institute
6120D Executive Boulevard, MSC 7164
Bethesda, MD 20892-7164
Telephone: (301) 496-5983
Fax: (301) 402-0528
Last Updated: 1/29/02