ocular migraine
Obviously not seen the person, or quizzed them, but this has all the hallmarks of a scintillating scotoma, which is typical of ocular migraine.
At 26 it is highly unlikely to be a tia. On what basis was the last poster labelled as this. ...I presume they have had a scan with positive findings (which most tia's will not have) or there are other aspects that the last poster has not made clear.Otherwise it is a life changing diagnosis for someone in your business.
Also the story does not fit with a brain tumour, so highly unlikely ...the symptoms would be more persistent and progressive, with other things.
It sounds like the ocular migrains I used to have. Zigzags are typical of migranous aura, but they can be twinkling shimmering areas of distortion too.
You can also get visual distortion.... eg. like looking through a telescope the wrong way.....not ideal if you are about to land a plane!!!!
Has he ever suffered from headaches particularly with nausea or vomiting?
triggers are as mentioned, but the biggest one is tiredness or stress/pressure. Or to be more exact when the pressure is easing.
so If you have had a busy and overtiring period on the roster, it happens on your day off!!!
Sleep will ease it, and in my experience, and that of other migraine sufferers you get a period of dreamy rem sleep that often makes a migraine go.
Most sufferers of migraine will be diagnosed on history and not on investigations like scans. Basic exam like bloodpressure and cranial nerves will presumably have been done for the periodic licence medicals.
It may come periodically, but some people get one attack, never to be repeated, or not repeated for many years.