Amaurosis fugax under the age of 40 years.

Sixteen patients who presented under the age of 40 years with amaurosis fugax have been studied. Follow up from the time of presentation was one to 13 years with a median of 3 years. One patient whose attacks of uniocular visual loss were associated with headache developed a permanent uniocular field defect. None of the other patients has suffered permanent visual loss, or had symptoms of cerebral or myocardial ischaemia. All angiograms were normal and it is suggested that carotid angiography is unnecessary in this age group. Four out of ten patients studied demonstrated evidence of platelet hyperaggregability to low concentrations of arachidonic acid and adenosine diphosphate with spontaneous aggregation. However, in six patients treated with aspirin, including three with previous platelet hyperaggregability, there was no change in the frequency of their attacks implying that the observed platelet abnormalities were not the cause of the amaurosis fugax.