flashing in eye

My wife was diagnosed with a corroidal melanoma and had radioactive plaque therapy about 4 months ago to treat it.She had a check up 5 weeks after the operation and was told it was reactive and was right on the spot.However,for the past few weeks,she has been getting what she describes as a flash at the bottom of that eye,it lasts for less than a second,and it only happens in very dim light,mostly when she wakens through the night.She sometime gets about 3-4 a short time apart,but never gets it through the day when obviously the light is much brighter.Again,she sometimes goes for a few days without the flashes before they come back again.She is worried that there is something wrong or that the radiation is not working.Could anyone tell me if this is something to worry about or is this the way that the radioactive therapy works and these flashes are a sign that it is working.I would be very grateful for any help since she is worried sick about it.

[Ray T Oyakawa, MD]

This type of flash is usually due to vitreous traction.  You need to have it checked by your doctor.

Dr. O.

[trebor45]

I had that this last month, along with floaters, turned out the vitreous gel had separated from retina, now recovering from 3rd surgery, 1st two were laser, and they didnt work, had major microsurgery the 3rd time, and retina reattached itself with a fold in it, my vision is now permanently distorted, I would advise she get to her eye doctor asap, as i waited three days before i saw mine, if i would have got in right away, laser treatment would have fixed it, Good Luck

[newmeriva60]

Thanks very much for the answers.The problem is that she has other serious health issues and she is getting to breaking point mentally and feels that she can't take any more.She is absolutely petrified of going to the eye clinic in 2 weeks time for a check up,in fact,I don't know if I'll manage to get her there.She keeps saying that she isn't going and I can't force her to go.