Objective: Description of the patients recruited into the Central Vein Occlusion Study (CVOS) and of the status of their eyes at time of study entry. This population is currently being followed for evaluation of photocoagulation treatment for eyes with central retinal vein occlusion (CVO) and natural history.
Design: Prospective multicenter cohort study incorporating 2 natural history groups and 2 randomized controlled clinical trials.
Setting: Eight ophthalmic practices in the USA and 1 in France, primarily associated with academic centers.
Patients: Seven hundred and twenty-five patients with CVO (728 eyes) divided into 4 study groups on the basis of the perfusion status of the retina and presence of decreased vision associated with macular edema: perfused, nonperfused, indeterminate, and macular edema.
Interventions: Nonperfused group: random assignment to panretinal photocoagulation or watchful waiting. Macular edema group: random assignment to grid pattern photocoagulation or watchful waiting. Natural history groups: no intervention.
Main outcome measures: Description of population and eyes based upon clinical examination and central assessment of fundus angiography, iris photographs, and stereo color fundus photographs.
Main results: Mean age for the 725 patients is 65 years, with 43% of patients in the study age 70 or older. Despite the older age of this population, more than half (53%) of the patients are male. One hundred and eighty-one patients were randomized into the nonperfused group and 155 into the macular edema group. Follow-up in the CVOS will be completed in February 1994 when most patients are expected to have completed the planned 3 years.
Conclusions: Recruitment has been successfully completed in this prospective study and the design and baseline results are presented.