Complications of Age-Related Macular Degeneration Prevention Trial (CAPT)

Complications of Age-Related Macular Degeneration Prevention Trial (CAPT)

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.

Study Overview

• Status: Completed
• Conditions: Macular Degeneration
• Intervention / Treatment: Procedure: Low-Intensity Laser Treatment

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 Type: Interventional
• Enrollment (Actual): 1052
• Phase: Phase 3

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Mesa, Arizona, United States, 85201
      • Retinal Consultants of Arizona, Ltd.
    • Peoria, Arizona, United States, 85351
      • Retinal Consultants of Arizona, Ltd.
  • California
    • San Francisco, California, United States, 94107
      • West Coast Retina Medical Group, Inc.
  • Florida
    • Tampa, Florida, United States, 33612-4766
      • University of South Florida Eye Institute
  • Georgia
    • Atlanta, Georgia, United States, 30322
      • Emory Eye Center
  • Illinois
    • Chicago, Illinois, United States, 60611
      • Northwestern University
    • Harvey, Illinois, United States, 60426
      • Illinois Retina Associates, S.C.
  • Iowa
    • Iowa City, Iowa, United States, 55242-1091
      • University of Iowa
  • Kentucky
    • Louisville, Kentucky, United States, 40202-1594
      • Ophthalmology & Visual Sciences at the University of Louisville, School of Medicine
  • Maryland
    • Baltimore, Maryland, United States, 21287-9223
      • The Johns Hopkins University
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Ophthalmic Consultants of Boston
  • Michigan
    • Royal Oak, Michigan, United States, 48073
      • Associate Retinal Consultants, P.C.
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic
  • Missouri
    • St. Louis, Missouri, United States, 63110
      • Barnes Retina Institute
  • New Jersey
    • Edison, New Jersey, United States, 08820
      • Retina-Vitreous Center, P.A.
    • Lakewood, New Jersey, United States, 08701
      • Retina-Vitreous Center, P.A.
  • North Carolina
    • Charlotte, North Carolina, United States, 28204
      • Southeast Clinical Research Associates
  • Ohio
    • Cleveland, Ohio, United States, 44122
      • Retina Associates of Cleveland
    • Columbus, Ohio, United States, 43210
      • The Ohio State University, Department of Ophthalmology
  • Oregon
    • Portland, Oregon, United States, 97210
      • Retina Northwest, P.C.
    • Portland, Oregon, United States, 97201-4197
      • Casey Eye Institute
  • Pennsylvania
    • Philadelphia, Pennsylvania, United States, 19104
      • Scheie Eye Institute
  • Texas
    • Dallas, Texas, United States, 75231
      • Texas Retina Associates
  • Wisconsin
    • Madison, Wisconsin, United States, 53705
      • University of Wisconsin - Madison, Department of Ophthalmology and Visual Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Single Group Assignment
• Masking: Single

Number of Arms

1

Arms and Interventions

Participant Group / 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in visual acuity (3-line loss)	5 years

Secondary Outcome Measures

Outcome Measure	Time Frame
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

Collaborators and Investigators

• Sponsor: National Eye Institute (NEI)
• Investigators: Study Chair: Stuart L Fine, MD, Scheie Eye Institute, The University of Pennsylvania School of Medicine

Publications and helpful links

General Publications

• Brader HS, Ying GS, Martin ER, Maguire MG; Complications of Age-Related Macular Degeneration Prevention Trial-CAPT Research Group. New grading criteria allow for earlier detection of geographic atrophy in clinical trials. Invest Ophthalmol Vis Sci. 2011 Nov 29;52(12):9218-25. doi: 10.1167/iovs.11-7493.

Helpful Links

• NEI Clinical Studies Database

Study record dates

Study Major Dates

• Study Start: May 1, 1999
• Study Completion (Actual): June 1, 2006

Study Registration Dates

• First Submitted: September 23, 1999
• First Submitted That Met QC Criteria: September 23, 1999
• First Posted (Estimate): September 24, 1999

Study Record Updates

• Last Update Posted (Estimate): March 24, 2010
• Last Update Submitted That Met QC Criteria: March 23, 2010
• Last Verified: December 1, 2007

More Information

Terms related to this study

• Keywords: Age-Related Macular Degeneration
• Additional Relevant MeSH Terms: Eye Diseases; Retinal Degeneration; Retinal Diseases; Macular Degeneration
• Other Study ID Numbers: NEI-70