I'm pretty sure that if headaches are resolved by getting glasses, then they weren't migraines- they were a different kind of headache. I am of course no expert, but not all severe headaches are migraines. Eyestrain headaches can certainly be very painful.
My DD2 is three, well actually she'll be four in two weeks, but she's been suffering from cyclic vomiting syndrome since toddlerhood, which is a disorder related to migraine. The difference is that her primary symptoms are abdominal pain and vomiting, and the headache is mild, but the disorder functions like true migraines and is treated similarly. She wakes up in the morning complaining of vision disturbances and abdominal pain. Fifteen or twenty minutes later, she starts vomiting, and vomits eight or ten times an hour for between three and ten hours. Then she falls asleep, and wakes up completely recovered and asking for food. During an episode, she's extremely pale, has big black circles under her eyes, has periods of serious unresponsiveness (like a waking coma), is sensitive to light, and is intensely irritable.
So far we're relying on becoming aware of triggers, which has reduced the frequency to less often than once a month. When she does have an episode, we're using strong painkillers, and anti-emetics, to relieve the symptoms. This has reduced episodes to under three hours. We've elected to pass on preventative meds until she's ready to go to school, largely because she's having only six or seven episodes a year at this point, and her episodes are fairly short compared to those of most kids with migraine now that we have the anti-emetics. Once she starts school, if she's missing days because of episodes, we'll go to preventatives.
Triggers we've identified: chocolate (but only after noon-- chocolate in the mornings seems to be fine), dehydration, skipping meals, tantrums, and big changes in the weather. She's had her worst episodes after drinking cocoa before bed, after skipping dinner when she didn't like what I'd cooked, and before big snowstorms. The tantrum ones, and the weather ones, are the worst, because I have so little control over those. I can't stop a three year old from occasionally losing her gourd and throwing a fit, not without catering to her whims in a way that wouldn't be good for her, and I definitely can't do anything to stop weather-- it's low/high pressure changes that seem to affect her.
