Central Vein Occlusion Study (CVOS)



Sponsors


Source

National Eye Institute (NEI)

Brief Summary

To determine whether photocoagulation therapy can help prevent iris neovascularization in
eyes with central vein occlusion (CVO) and evidence of ischemic retina.

To assess whether grid-pattern photocoagulation therapy will reduce loss of central visual
acuity due to macular edema secondary to CVO.

To develop new data describing the course and prognosis for eyes with CVO.

Detailed Description

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.

Overall Status

Completed

Start Date

1988-08-01

Completion Date

1994-02-01

Primary Completion Date

N/A

Phase

Phase 3

Study Type

Interventional


Conditions


Intervention

Intervention Type

Procedure

Intervention Name



Eligibility

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.

Gender

All

Minimum Age

21 Years

Maximum Age

N/A

Healthy Volunteers

No


Verification Date

2009-09-01

Lastchanged Date

N/A

Firstreceived Date

N/A

Keywords


Has Expanded Access

No

Condition Browse


Firstreceived Results Date

N/A

Reference

Citation

Baseline and early natural history report. The Central Vein Occlusion Study. Arch Ophthalmol. 1993 Aug;111(8):1087-95.

PMID

7688950


Citation

Clarkson JG. Central Vein Occlusion Study: photographic protocol and early natural history. Trans Am Ophthalmol Soc. 1994;92:203-13; discussion 213-5.

PMID

7533959


Citation

Evaluation of grid pattern photocoagulation for macular edema in central vein occlusion. The Central Vein Occlusion Study Group M report. Ophthalmology. 1995 Oct;102(10):1425-33.

PMID

9097788


Citation

A randomized clinical trial of early panretinal photocoagulation for ischemic central vein occlusion. The Central Vein Occlusion Study Group N report. Ophthalmology. 1995 Oct;102(10):1434-44.

PMID

9097789


Citation

Natural history and clinical management of central retinal vein occlusion. The Central Vein Occlusion Study Group. Arch Ophthalmol. 1997 Apr;115(4):486-91. Erratum in: Arch Ophthalmol 1997 Oct;115(10):1275.

PMID

9109757



Firstreceived Results Disposition Date

N/A

Study Design Info

Allocation

Randomized

Primary Purpose

Treatment


Study First Submitted

September 23, 1999

Study First Submitted Qc

September 23, 1999

Study First Posted

September 24, 1999

Last Update Submitted

September 16, 2009

Last Update Submitted Qc

September 16, 2009

Last Update Posted

September 17, 2009


ClinicalTrials.gov processed this data on August 24, 2018

Conditions

Conditions usually refer to a disease, disorder, syndrome, illness, or injury. In ClinicalTrials.gov, conditions include any health issue worth studying, such as lifespan, quality of life, health risks, etc.
Interventions

Interventions refer to the drug, vaccine, procedure, device, or other potential treatment being studied. Interventions can also include less intrusive possibilities such as surveys, education, and interviews.
Study Phase

Most clinical trials are designated as phase 1, 2, 3, or 4, based on the type of questions that study is seeking to answer:

In Phase 1 (Phase I) clinical trials, researchers test a new drug or treatment in a small group of people (20-80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.

In Phase 2 (Phase II) clinical trials, the study drug or treatment is given to a larger group of people (100-300) to see if it is effective and to further evaluate its safety.

In Phase 3 (Phase III) clinical trials, the study drug or treatment is given to large groups of people (1,000-3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.

In Phase 4 (Phase IV) clinical trials, post marketing studies delineate additional information including the drug's risks, benefits, and optimal use.

These phases are defined by the Food and Drug Administration in the Code of Federal Regulations.



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