Normal tension glaucoma and primary open angle glaucoma associated with increased platelet aggregation

On purpose of the present study was to evaluate platelet aggregation and fi brinolytic systems in patients with normal tension glaucoma (NTG) or primar y open angle glaucome (POAG). For platelet aggregation, we photoelectrophot ometrically investigated adenosine diphosphate (ADP) or collagen-induced pl atelet aggregation in consecutively selected patients with glaucoma (22 pat ients with NTG and 13 patients with POAG) and 42 glaucoma free control subj ects with normal ocular findings. The aggregation patterns of the patients' platelets reacted abnormally to ADP 1 muM or collagen 0.5 mug/ml as eviden ced by secondary aggregation were compared with those of control subjects. For blood coagulative and fibrinolytic systems, rye measured prothrombin ti me, activated partial thromboplastin time, fibrinogen, thrombin-antithrombi n III complex (TAT), alpha (2) plasmin inhibitor-plasmin complex. Seventeen of 22 patients (77%) with NTG and 5 of 13 patients (38%) with POAG showed abnormal secondary aggregation. A significant difference was observed betwe en the two groups. No control subjects showed abnormal secondary aggregatio n. In the fibrinolytic test, all the parameters examined showed within norm al ranges, although the log(10)(TAT) value was higher in NTG than in POAG. Results of the present study suggested that increased platelet aggregation as defined by ADP or collagen induced abnormal secondary aggregation in vit ro is frequently associated with glaucoma patients and this tendency is mor e apparent in NTG than that in POAG. (C) 2001 Tohoku University Medical Pre ss.