Purpose To examine the change of optic disc blood flow in primary open angle glaucoma(POAG) patients after cold provocation test and nifedipine administration． Methods Using Heidelberg retinal flowmetry (HRF),the blood flow of optic disc of glaucoma patients and normal control subjects were measured under basal condition, after cold provocation test,and after nifedipine administration. Results The mean optic disc blood volume and flow of POAG patients reduced from 27.1 and 545.4 to 22.3 and 452.4 after cold provocation test (Plt;0.05),and increased to 29.0 and 579.5 after nifedipine adminstration(Plt;0.05).The changes of mean optic disc blood flow of patients with a history of cold extremities show statistic significance compared with whom without such history (Plt;0.05)). Conclusion The changes of blood flow of optic disc in POAG patients may be influenced by cold stimuli and administration of nifedipine,and the history of cold extremities might be connected with the change of optic disc blood flow in POAG patients. (Chin J Ocul Fundus Dis,2000,16:85-87)