CAPT: Complications of Age-Related Macular Degeneration Prevention Trial
Study Details
Study Description
Brief Summary
To determine whether application of low-intensity laser treatment of eyes with drusen in the macula can prevent later complications of age-related macular degeneration and thereby preserve visual function.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
Phase 3 |
Detailed Description
Complications of age-related macular degeneration (AMD) are the leading cause of severe vision loss among people aged 65 and over in the United States and many Western countries. Most, (approximately 90 percent), of this vision loss is due to the neovascular (or wet) form of AMD. The word neovascular describes the development of new, abnormal blood vessels in the back of the eye. Unfortunately, the majority of these new vessels are not amenable to currently available treatments.
The first sign that an eye may develop AMD is the presence of drusen, yellowish deposits under the retina. Current data suggests that eyes with large drusen are at increased risk for developing the vision threatening complications of AMD. Since the 1970s investigators have reported consistently that laser photocoagulation causes a reduction in large drusen. However, results of the effects of laser treatment on preventing later complications of AMD have been less consistent and based on relatively small numbers of patients.
Further study into the ability of a treatment to prevent vision loss from the advanced forms of AMD would have profound public health implications. A treatment that could reduce the risk of developing neovascularization by 30 percent might reduce the risk of blindness from AMD by one half. The Complications of Age-related Macular Degeneration Prevention Trial (CAPT) will assess whether treating drusen by laser photocoagulation reduces the risk of loss of visual acuity.
The CAPT is a multi-center, prospective, randomized clinical trial designed to assess the safety and effectiveness of low-intensity laser treatment in preventing vision loss among patients with large drusen in both eyes. A total of 1052 participants were enrolled in the study. Participants had one eye randomly assigned to laser treatment performed by a CAPT-certified ophthalmologist. The other eye was not treated. Both eyes were observed carefully for any changes for a period of five years. The effectiveness of the treatment was assessed using the following criteria:
Change in visual acuity (primary outcome measure of the study)
Incidence of complications of AMD such as neovascularization, serous detachment of the pigment epithelium, and geographic atrophy
Changes in contrast threshold and critical print size for reading
Quality of life assessments for patients, using the Visual Function Questionnaire 25 (VFQ-25), were conducted at the time of enrollment and at 5 years.
STUDY RESULTS:
Follow-up of patients was excellent; less than 3% of visual acuity examinations were missed. At 5 years, 188 (20.5%) treated eyes and 188 (20.5%) observed eyes had visual acuity scores ≥3 lines worse than at the initial visit (p= 1.00). The cumulative 5-year incidence rates for treated and observed eyes for CNV were 13.3% and 13.3% (p=0.95), respectively; and for GA were 7.4% and 7.8% (p=0.64), respectively. The contrast threshold doubled in 23.9% of treated eyes and in 20.5% of observed eyes (p=0.40). The critical print size doubled in 29.6% of treated eyes and in 28.4% of observed eyes (p=0.70). Seven (0.7%) treated eyes and 14 (1.3%) observed eyes had an adverse event of a ≥6 -line loss in visual acuity in the absence of late age-related macular degeneration or cataract.
As applied in CAPT, low intensity laser treatment did not demonstrate a clinically significant benefit on vision in eyes of people with bilateral large drusen.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: 1 Laser treatment |
Procedure: Low-Intensity Laser Treatment
Initial: 60 barely visible burns, grid pattern. Re-treatment at 12 months: 30 barely visible burns, focal treatment.
|
Outcome Measures
Primary Outcome Measures
- Change in visual acuity (3-line loss) [5 years]
Secondary Outcome Measures
- Incidence of complications of AMD such as neovascularization, serous detachment of the pigment epithelium, and geographic atrophy [5 years]
- Changes in contrast threshold and critical print size for reading [5 years]
Eligibility Criteria
Criteria
Patients eligible for CAPT can be either male or female and meet the following criteria:
Age at least 50 years old
Vision in each eye must measure 20/40 or better.
At least 10 large drusen in each eye
Available for follow-up examinations for 5 years after enrollment
Final eligibility is determined through a detailed eye examination by a CAPT-certified ophthalmologist.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Retinal Consultants of Arizona, Ltd. | Mesa | Arizona | United States | 85201 |
| 2 | Retinal Consultants of Arizona, Ltd. | Peoria | Arizona | United States | 85351 |
| 3 | West Coast Retina Medical Group, Inc. | San Francisco | California | United States | 94107 |
| 4 | University of South Florida Eye Institute | Tampa | Florida | United States | 33612-4766 |
| 5 | Emory Eye Center | Atlanta | Georgia | United States | 30322 |
| 6 | Northwestern University | Chicago | Illinois | United States | 60611 |
| 7 | Illinois Retina Associates, S.C. | Harvey | Illinois | United States | 60426 |
| 8 | University of Iowa | Iowa City | Iowa | United States | 55242-1091 |
| 9 | Ophthalmology & Visual Sciences at the University of Louisville, School of Medicine | Louisville | Kentucky | United States | 40202-1594 |
| 10 | The Johns Hopkins University | Baltimore | Maryland | United States | 21287-9223 |
| 11 | Ophthalmic Consultants of Boston | Boston | Massachusetts | United States | 02114 |
| 12 | Associate Retinal Consultants, P.C. | Royal Oak | Michigan | United States | 48073 |
| 13 | Mayo Clinic | Rochester | Minnesota | United States | 55905 |
| 14 | Barnes Retina Institute | St. Louis | Missouri | United States | 63110 |
| 15 | Retina-Vitreous Center, P.A. | Edison | New Jersey | United States | 08820 |
| 16 | Retina-Vitreous Center, P.A. | Lakewood | New Jersey | United States | 08701 |
| 17 | Southeast Clinical Research Associates | Charlotte | North Carolina | United States | 28204 |
| 18 | Retina Associates of Cleveland | Cleveland | Ohio | United States | 44122 |
| 19 | The Ohio State University, Department of Ophthalmology | Columbus | Ohio | United States | 43210 |
| 20 | Casey Eye Institute | Portland | Oregon | United States | 97201-4197 |
| 21 | Retina Northwest, P.C. | Portland | Oregon | United States | 97210 |
| 22 | Scheie Eye Institute | Philadelphia | Pennsylvania | United States | 19104 |
| 23 | Texas Retina Associates | Dallas | Texas | United States | 75231 |
| 24 | University of Wisconsin - Madison, Department of Ophthalmology and Visual Sciences | Madison | Wisconsin | United States | 53705 |
Sponsors and Collaborators
- National Eye Institute (NEI)
Investigators
- Study Chair: Stuart L Fine, MD, Scheie Eye Institute, The University of Pennsylvania School of Medicine
Study Documents (Full-Text)
None provided.More Information
Additional Information:
Publications
None provided.- NEI-70