Complications of Age-Related Macular Degeneration Prevention Trial

Macular Degeneration Clinical Trial

— CAPT  

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00000167
• Other study ID #: NEI-70
• Status: Completed
• Phase: Phase 3
• First received: September 23, 1999
• Last updated: March 23, 2010
• Start date: May 1999
• Est. completion date: June 2006

Study information

• Verified date: December 2007
• Source: National Eye Institute (NEI)
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 1052
• Est. completion date: June 2006
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 50 Years and older

Eligibility

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 Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Single Blind (Outcomes Assessor), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Macular Degeneration

Intervention

Procedure:
• Low-Intensity Laser Treatment
Initial: 60 barely visible burns, grid pattern. Re-treatment at 12 months: 30 barely visible burns, focal treatment.

Locations

Country	Name	City	State
United States	Emory Eye Center	Atlanta	Georgia
United States	The Johns Hopkins University	Baltimore	Maryland
United States	Ophthalmic Consultants of Boston	Boston	Massachusetts
United States	Southeast Clinical Research Associates	Charlotte	North Carolina
United States	Northwestern University	Chicago	Illinois
United States	Retina Associates of Cleveland	Cleveland	Ohio
United States	The Ohio State University, Department of Ophthalmology	Columbus	Ohio
United States	Texas Retina Associates	Dallas	Texas
United States	Retina-Vitreous Center, P.A.	Edison	New Jersey
United States	Illinois Retina Associates, S.C.	Harvey	Illinois
United States	University of Iowa	Iowa City	Iowa
United States	Retina-Vitreous Center, P.A.	Lakewood	New Jersey
United States	Ophthalmology & Visual Sciences at the University of Louisville, School of Medicine	Louisville	Kentucky
United States	University of Wisconsin - Madison, Department of Ophthalmology and Visual Sciences	Madison	Wisconsin
United States	Retinal Consultants of Arizona, Ltd.	Mesa	Arizona
United States	Retinal Consultants of Arizona, Ltd.	Peoria	Arizona
United States	Scheie Eye Institute	Philadelphia	Pennsylvania
United States	Casey Eye Institute	Portland	Oregon
United States	Retina Northwest, P.C.	Portland	Oregon
United States	Mayo Clinic	Rochester	Minnesota
United States	Associate Retinal Consultants, P.C.	Royal Oak	Michigan
United States	West Coast Retina Medical Group, Inc.	San Francisco	California
United States	Barnes Retina Institute	St. Louis	Missouri
United States	University of South Florida Eye Institute	Tampa	Florida

Sponsors (1)

Lead Sponsor	Collaborator
National Eye Institute (NEI)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in visual acuity (3-line loss)		5 years	No
Secondary	Incidence of complications of AMD such as neovascularization, serous detachment of the pigment epithelium, and geographic atrophy		5 years	No
Secondary	Changes in contrast threshold and critical print size for reading		5 years	No

External Links

•   NEI Clinical Studies Database