The study of the reactions of the bulbar conjunctival vessels in man to physical and chemical stimuli has revealed vasoconstriction, vasodilatation, and alterations in the flow of blood cells. The appearance and behavior of these vessels in various clinical conditions have been described.
A constriction preceding and a dilatation of both large and minute conjunctival vessels during the migraine attack have been observed.1-3 During the latter phases of pregnancy the capillary blood flow and the number of visible capillaries are often reduced.4,5 In the eight to five days premenstrually, vasoconstriction and increase in spontaneous vasomotor activity in the capillary bed and tissue ischemia can be observed. At or just prior to the onset of menstruation there is arterial dilatation and a reduced velocity of blood flow.6 Also, there are bulbar conjunctival vascular changes accompanying diabetes mellitus, arteriosclerosis (with and without renal impairment), and essential hypertension.7,8
The conjunctival circulation in disorders