“My eye’s gone blurry and aches — it’s probably just a migraine”

Subacute MONOCULAR visual loss/blur with PAIN ON EYE MOVEMENT and impaired COLOUR vision (red desaturation), ± a relative afferent pupillary defect, is the classic triad of OPTIC NEURITIS — not a migraine (transient positive visual phenomena with headache) or eye strain — and it is frequently the first presentation of MULTIPLE SCLEROSIS. A previously-ignored transient neurological symptom (here leg numbness) suggests a prior demyelinating event and raises the MS suspicion (dissemination in time/space). The action is urgent ophthalmology/neurology assessment (acuity, fields, colour vision, fundoscopy, RAPD), MRI (brain ± orbits) and neurology referral — not primary-care drops; steroids may shorten the episode (a specialist decision) and vision usually recovers well. The examinable hidden agenda is avoidance of a feared MS diagnosis (a relative has it), using the migraine label as a shelter, plus an outdated "wheelchair" fear. Recognise the picture, take the old symptom seriously, investigate urgently, handle the MS possibility honestly (no premature labelling, no false reassurance) with balanced modern information (MS is variable and highly treatable now; early treatment gives the best outcomes), and safety-net new/worsening neurology.