Macular Photocoagulation Study (MPS)

June 23, 2005 updated by: National Eye Institute (NEI)

To evaluate laser treatment of choroidal neovascularization (CNV) through randomized, controlled clinical trials. The Macular Photocoagulation Study (MPS) consisted of three sets of randomized, controlled clinical trials. Change in best-corrected visual acuity from baseline was the primary outcome for all MPS trials. Other measures of vision are evaluated in each set of trials. The purpose of each is described below.

Argon Study: To determine whether argon blue-green laser photocoagulation of leaking abnormal blood vessels in choroidal neovascular membranes outside the fovea (200 to 2,500 microns from the center of the foveal avascular zone [FAZ]) is of benefit in preventing or delaying loss of central vision in patients with age-related (senile) macular degeneration (AMD), presumed ocular histoplasmosis (POH), and idiopathic neovascular membranes (INVM). A separate trial was conducted for each of the three underlying conditions.

Krypton Study: To determine whether krypton red laser photocoagulation of choroidal neovascular lesions with the posterior border 1 to 199 microns from the center of the FAZ is of benefit in preventing or delaying large losses of visual acuity in patients with AMD, POH, and INVM. A separate trial was conducted for each of the three underlying conditions.

Foveal Study: To determine whether laser photocoagulation is of benefit in preventing or delaying further visual acuity loss in patients with new (never treated) or recurrent (previously treated with laser photocoagulation) choroidal neovascularization under the center of the FAZ. Two separate trials, one for each type of lesion, were carried out.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

In each randomized trial conducted by the MPS Group, focal laser photocoagulation was compared to observation without treatment. Patients were assigned to laser treatment or to observation with equal probability. The first set of MPS randomized trials, the Argon Study, focused on the effectiveness of photocoagulation with argon blue-green laser in eyes with discrete extrafoveal choroidal neovascularization. The study investigators, who began recruiting patients in 1979, estimated that 550 patients with AMD and 750 with POH would be required. Follow-up was to continue for 5 years to determine whether argon laser photocoagulation treatment could prevent or delay visual acuity loss in these patients.

After the initiation of the Argon Study, a new krypton red laser became available. The new wavelength offered theoretical advantages over the argon laser for treating CNV that extended inside the FAZ of the macula. The Krypton Study design was analogous to the Argon Study, with the investigation of three underlying conditions, except that CNV was closer to the FAZ center.

The third set of MPS clinical trials, the Foveal Study, was designed to determine whether laser photocoagulation was effective for delaying or preventing further visual acuity loss in AMD patients who have subfoveal CNV. Among patients assigned to laser treatment in the Foveal Study, argon laser treatment was compared with krypton red laser treatment of these lesions. The investigators originally projected that about 350 patients would be required for each clinical trial of the Foveal Study.

Study Type

Interventional

Phase

  • Phase 3

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Common Eligibility Criteria for the Argon, Krypton, and Foveal Studies:

To be eligible, men and women must have been experiencing visual symptoms attributable to the macular lesion, such as decreased visual acuity or Amsler grid distortion, at the time of entry into the study. They also must have had visible, well-demarcated hyperfluorescence characteristic of classic choroidal neovascularization on fluorescein angiography. AMD patients were 50 years of age or older and had drusen visible in the macula of at least one eye. POH patients were at least 18 years old and had at least one characteristic histo spot in one or both eyes. INVM patients were at least 18 years old and had no evidence of AMD, POH, angioid streaks, high myopia, diabetic retinopathy, or any other condition that could be the cause of the neovascularization. In particular, INVM patients had neither drusen greater than MPS Standard Photograph No. 1.1 nor histo spots in either eye.

Additional Patient Eligibility Criteria for the Argon Study:

Each patient had a visible serous detachment of the sensory retina with a diffuse area of leakage, discrete choroidal neovascularization outside the fovea (200-2,500 microns from the center of the FAZ), and visual acuity of 20/100 or better in the study eye.

Additional Patient Eligibility Criteria for the Krypton Study:

All patients had a neovascular lesion consisting of neovascularization and possibly blood and/or pigment that extended into the FAZ. The posterior border of CNV could extend as close as 1 micron to the FAZ center. Visual acuity of the study eye was 20/400 or better.

Additional Patient Eligibility Criteria for the Foveal Study:

Only patients with AMD were eligible for this study. Fluorescein angiography of the eligible eye had to show evidence of a leaking choroidal neovascular membrane, some part of which extended under the center of the FAZ, or a neovascular lesion consisting of an old laser treatment scar and contiguous leaking neovascularization within 150 microns of the center of the FAZ. New, never-treated subfoveal lesions were less than four disc areas in size. Recurrent lesions were less than six disc areas in size, including the old treatment scar and new neovascularization. Best-corrected visual acuity was no better than 20/40 and no worse than 20/320.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: TREATMENT
  • Allocation: RANDOMIZED

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Eye Institute (NEI)

Publications and helpful links

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General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

February 1, 1979

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)

June 24, 2005

Last Update Submitted That Met QC Criteria

June 23, 2005

Last Verified

June 1, 2002

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NEI-60

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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