Yes, light sensitivity occaisionally is a problem for me, like Gareth I've found that if I make sure I drink a lot (proper water not the other kind

) I find it's happening less. But occasionally there's nothing that stops it or touches the pain - only tried over the counter pain killers though ....
Sometimes I've resorted to two pairs of sunglasses a dark grey polaroid pair over a brown pair underneath and that's just to be able to see enough to get home on the bus, cross a road etc.
As well as the safety specs that Gareth suggested the RNIB do over glasses in various shades which fit over prescription glasses, if you have them, or normal sunglasses for added effect. I did muse at one time as I like my theories that it was a particular frequency of light and if only you could get the right type of filtering device (coz that's what sunglasses do) then the problem would not be as bad, but it's just the sun.
I did boast that at one time I had 357 pairs of sunglasses but I've had a clear out of the scratched ones and ones that aren't dark enough, and the Elvis type vintage 70's pair went on ebay for a few hundred quid as it happens...
The only thing which stops it happening or makes it happen less frequently is keep general health good, drink plenty to make sure you are well hydrated coz that seems to make a diference, any eye drops that you use and sun glasses. Not very helpful at all, sorry.
Oh and if you have any corneal scratches/scars that may make it worse.
If only we could guarantee it won't happen at all as it's constantly at the back of yer mind if there's even a glimmer of blue in the sky (not that common in Manchester!), and sometimes even the reflections from mirrors, and puddles(which are common) get to you.
Good luck
Tam