Protein C, protein S and antithrombin III deficiencies in retinal vein occlusion.

Abstract

The role of decreased levels of protein C, protein S and antithrombin III were investigated in patients with branch and central retinal vein occlusion. Forty-five patients with retinal vein occlusion and 20 healthy subjects as a control group was studied. Fourteen patients (31%) had central retinal vein occlusion and 31 (69%) had branch retinal vein occlusion. The concentrations of protein C, protein S and antithrombin III were measured. Plasma levels of protein C, protein S and antithrombin III were not reduced in the control group. Six of the 14 central retinal vein occlusion cases and 3 of the 31 retinal branch vein occlusion cases had decreased levels of protein C. One of the 14 central retinal vein occlusion cases and 1 of the 31 retinal branch vein occlusion cases had decreased levels of protein S. Antithrombin III was reduced in 1 patient of the 31 retinal branch vein occlusions. We found statistically significant differences for number of cases with protein C deficiency between the central retinal vein occlusion cases and the branch retinal vein occlusion cases (p<0.05). Deficiency of anticoagulant proteins, especially protein C, may play a role in the etiology of retinal vein occlusion. Measurement of these parameters may be useful in preventing venous thrombosis elsewhere in the body.