To study the vasoactivity of glaucoma patients with four previously described and distinct disc appearances potentially representative of primary open angle glaucoma subgroups.Patients with pure examples of four glaucomatous optic disc types--focal ischaemic, myopic glaucomatous, senile sclerotic, and those with generalised cup enlargement, were selected. A detailed ophthalmic, systemic, drug, and smoking history was taken from the patients who, in addition, underwent assessment of peripheral vasospasm with a laser Doppler flowmeter. Differences between the groups were evaluated using an analysis of variance, Student's t test, Pearson's chi 2 test, Fisher's exact test together with Spearman's and Pearson's correlation tests.38 patients with focal ischaemic, 37 with myopic glaucomatous, 24 with senile sclerotic, and 24 with discs characterised by generalised cup enlargement met the selection criteria. The group of patients with focal ischaemic discs contained more women (66% versus 32%-50% in the other three groups; p = 0.01) and had a higher prevalence of vasospasm (63% versus 25%-49%; p = 0.01), migraine (32% versus 8%-19%; p = 0.02), and cold extremities (66% versus 17%-30%; p = 0.00003). The group of patients with senile sclerotic discs had a higher prevalence of systemic cardiovascular disease (58% versus 21%-30% in the other three groups; p = 0.01) and thyroid disease (21% cf 0%-8%; p = 0.01) and although their mean age was greater (76 years cf 55-65 years; p < 0.00001) the findings were independent of age. Smoking was unrelated to optic disc type.Vasospasm, previously associated with normal tension glaucoma, and generalised cardiovascular disease both appear to be specific risk factors for the development of particular subgroups of glaucoma and may be independent of absolute intraocular pressure levels exerting effects in patients with both "normal" or "raised" intraocular pressure. The simple assessment as to whether a glaucoma patient suffers from colder extremities than average appeared to be better at distinguishing the focal ischaemic type of glaucoma than the more complex determination of vasospasm using the laser Doppler flowmeter.