Purpose: To report a case of central retinal vein occlusion in the setting of type II protein C deficiency, and to describe the appropriate tests for detecting this clotting abnormality.
Design: Observational case report.
Methods: Retrospective review of clinical examination and laboratory findings.
Results: A 16-year-old girl was evaluated for progressive monocular vision loss occurring over a period of one month. Dilated fundus examination and fluorescein angiography revealed the presence of a central retinal vein occlusion. Hypercoagulable work-up demonstrated normal protein C antigen levels, but a marked reduction in protein C function, confirming a type II protein C deficiency.
Conclusions: Central retinal vein occlusion may be associated with type II protein C deficiency. Testing for protein C antigen levels and function is necessary for detection of both type I and type II protein C deficiency.