What symptom is associated with a classic migraine?

The manifestation of visual aura with flashing lights is indeed a well-documented symptom associated with classic migraines, also known as migraine with aura. This type of migraine is characterized by neurological symptoms that precede the headache phase, which can include visual disturbances such as bright, flashing lights, zigzag lines, or even partial vision loss. These visual auras are thought to be a result of cortical spreading depression, a phenomenon that alters brain activity temporarily, typically occurring 20-60 minutes before the onset of the headache.

In contrast, severe ocular pain is not a classic migraine symptom but could relate to other conditions, such as cluster headaches or eye disorders. Continuous dull headaches are often reflective of tension-type headaches rather than migraines, which tend to present as unilateral and pulsating. Lastly, fever and chills are systemic symptoms usually indicative of infections or other acute illnesses, rather than migraines, which do not typically present with systemic inflammatory signs. Thus, the presence of a visual aura with flashing lights is a distinguishing feature of classic migraines and confirms the correctness of this answer.