Purpose: Thrombophilic abnormalities and defects in the anticoagulant system, such as protein C or protein S deficiency, activated protein C resistance and factor V Leiden mutation, may produce retinal vascular occlusions.
Patients: Blood samples from 66 consecutive retinal vascular occlusion patients were obtained and analysed for protein C resistance and fibrinolysis activity. Other thrombophilic and standard laboratory coagulant tests were also carried out.
Results: An increased activity of factor VIII was found in 72% of the collective. Furthermore, 24% of all patients and 32% of patients younger than 45 years old were resistant to activated protein C. Nevertheless only one patient showed a homozygous factor V Leiden mutation.
Conclusion: Thrombophilic activity in cases of protein C resistance or factor V Leiden mutation may result in severe thrombotic manifestations in ocular vessels. Compared to the elderly, younger people showed a higher activated protein C resistance which seems be one of the most common causes for retinal vascular occlusion in this age group.