Laser and Antioxidant Treatment of Diabetic Macular Edema

NCT00055042 · Status: COMPLETED · Phase: PHASE1 · Type: INTERVENTIONAL · Enrollment: 40

Last updated 2008-03-04

No results posted yet for this study

Summary

This study will compare the side effects of two laser treatments for diabetic macular edema, a common condition in patients with diabetes. In macular edema, blood vessels in the retina-a thin layer of tissue that lines the back of the eye-become leaky and the retina swells. The macula-the center part of the retina that is responsible for fine vision-may also swell and cause vision loss. Traditional laser treatment (argon blue or green, or yellow) for macular swelling, or edema, causes scarring that can expand and possibly lead to more loss of vision. A different type of laser (diode) may have less damaging effects to the eye and fewer long-term adverse effects, but this is not known. The results of this study on side effects of the treatments will be used to design a larger study of effectiveness. The study will also examine whether vitamin E can reduce the damage caused by laser treatment. Patients with elevated cholesterol levels will be invited to participate in a cholesterol reduction part of the study to compare normal-pace cholesterol reduction with accelerated reduction.

Patients 18 years of age and older with type 1 or type 2 diabetes and macular edema may be eligible for this study. Candidates will be screened with the following tests and procedures:

* Medical history and physical examination.
* Eye examination to assess visual acuity (eye chart test) and eye pressure, and to examine pupils, lens, retina and eye movements. The pupils will be dilated with drops for this examination.
* Blood tests to measure cholesterol and vitamin E blood levels, blood clotting time, hemoglobin A1C (a measure of diabetes control), and to evaluate liver and kidney function.
* Eye photography to help evaluate the status of the retina and changes that may occur in the future. Special photographs of the inside of the eye are taken using a camera that flashes a bright light into the eye.
* Fluorescein angiography to evaluate the eye's blood vessels. A yellow dye is injected into an arm vein and travels to the blood vessels in the eyes. Pictures of the retina are taken using a camera that flashes a blue light into the eye. The pictures show if any dye has leaked from the vessels into the retina, indicating possible blood vessel abnormality.
* Multifocal electroretinogram to measure electrical responses generated within the retina. The test, which takes about 1-1/2 hours, is painless.

Participants will be randomly assigned to take 1600 IU of vitamin E or placebo (an inactive, look-alike pill) daily. After taking the pills for 3 months or more, patients who require laser treatment will be randomly assigned to one of the two laser therapies. (Patients with macular edema in both eyes will receive both treatments, one in each eye.) For these procedures, eye drops are put in the eye to numb the surface and a contact lens is placed on the eye during the laser beam application. Several visits may be required for additional laser treatments. The maximum number of treatments depends on how well they are working. Patients will return for follow-up visits 1, 3, and 6 months after the first treatment, and then every 6 months until either the patient returns for a 3-year visit; the last enrolled patient returns for the 1-year visit; or the patient requests to leave the study. During the follow-up visits, patients' response to treatment will be evaluated with repeat tests of several of the screening exams.

Conditions

Macular Edema
Diabetes Mellitus

Interventions

DRUG: Vitamin E

Sponsors & Collaborators

National Eye Institute (NEI)
lead NIH

Study Design

Purpose: TREATMENT

Eligibility

Sex: ALL
Healthy Volunteers: No

Timeline & Regulatory

Start: 2003-02-28
Completion: 2004-01-31

Countries

United States

Study Locations

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Entities

Diseases

Diabetes Mellitus