Central Vein Occlusion Study (CVOS)
Data Collection
Cardiovascular Diseases+5
+ Eye Diseases
+ Retinal Diseases
Treatment Study
Summary
Study start date: August 1, 1988
Actual date on which the first participant was enrolled.Central vein occlusion is a common retinal vascular disorder with potentially blinding complications. The two major complications are reduced central vision caused by macular edema and neovascular glaucoma caused by iris neovascularization. Other clinical trials have shown that laser photocoagulation is an effective treatment for complications found in diabetic retinopathy and branch vein occlusion, which have some features in common with CVO: neovascularization and reduced visual acuity caused by macular edema occur in all three disorders. Evidence from small-scale studies suggests that a grid pattern of photocoagulation reduces macular edema in CVO patients, although the associated changes in visual acuity are variable. The CVOS is a detailed investigation of grid pattern photocoagulation in a larger randomized group of patients. Eligible patients were divided into four groups: Group N: Eyes with extensive retinal ischemia (at least 10 disc areas of nonperfusion) were randomly assigned to receive panretinal photocoagulation or nontreatment unless iris neovascularization developed. Group M: Eyes with visual loss ascribable to macular edema were randomly assigned to receive grid-pattern photocoagulation or nontreatment. Group P: Eyes with relatively perfused retinas were followed to provide information about the natural history of the disease. Group I: Indeterminate eyes in which the retina could not be visualized accurately because of hemorrhage were followed in a natural history study. Green argon laser with a slit lamp delivery system was used for all treatments. Photographic documentation of retinal changes was obtained at entry, post-treatment, and at specified followup visits for a period of at least 3 years. The frequency of followup visits varied according to the group to which the CVO patient was assigned. Visual acuity, the primary outcome factor in the group with macular edema, was measured according to a modified Early Treatment Diabetic Retinopathy Study protocol at each visit.
Protocol
This section provides details of the study plan, including how the study is designed and what the study is measuring.Treatment Study
Eligibility
Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.Any sex
Biological sex of participants that are eligible to enroll.Over 21 Years
Range of ages for which participants are eligible to join.Healthy volunteers not allowed
If individuals who are healthy and do not have the condition being studied can participate.Conditions
Pathology
Criteria
Men and women must have been age 21 or older and willing to return for followup visits for 3 years following assignment into the appropriate group and randomization. Each of the four groups has specific eligibility criteria. Patients with retinal vascular disease other than that specified in the criteria, such as diabetic retinopathy, were ineligible. Patients with macular disease other than that due to CVO were ineligible for that portion of the study.