Intermittent angle-closure glaucoma in the presence of a white eye, posing as retinal migraine.

The differential diagnosis between primary and secondary headache may still represent a problematic clinical situation (1–3). Whereas the ‘de novo’ onsetof headache in a patient surely constitutes a reasonfor increased attention by the physician, difficulties occur when a new pathology arises in a patient already diagnosed as suffering from a primary form. This represents a risk in disregarding the supervening secondary cause, especially if the secondary headache remains quite similar in its clinical manifestation to the previous primary one. The following case, which recently came to our attention, is significant in this regard.