Seeing very faint rainbow halo -DR Hagan and others.

[MojaveNick]

I've just turned 20 and have noticed the weirdest thing after a conversation with my friends/family after one pointed out they saw a rainbow around my kitchens light bulb, then everyone agreed they could etc etc (these people are all 18-22 years old. After this it's led me on a weird confusing trail, because now I'm being very paranoid... constantly looking at lights - but anyway to the question. I've noticed at some degree/angle on mainly warm yellowish bulbs, the newer type ones, I can see a very faint rainbow halo underneath it, I have to look very closely and be standing in just the right spot, but even if I move away a few steps or even if I get right underneath it, it's gone? I had a complete eye exam 2 months ago, just for a check-up - I do have astigmatism in both eyes and experiencing very minor ghosting on light on dark sources. I experience these 'faint halos' in both eyes, symmetrically, I don't see it on white lights, sun glare, I've tested it out. It's only on a specific angle on some light bulbs and phone flashlights? I must admit I should say the 'rainbow' is more of just blue/green, MAYBE a extremely faint red - never noticed the other colours. I don't understand though, clearly to some extent it's 'normal' to see 'rainbows' because everyone at my house say they see it? Now I hate to be troublesome and ask them to check every single light source/angle that I've noticed because I did ask my best-friend and they agreed they've seen exactly what I describe as a 'common observation' and said don't worry, but how can I not when google exist. What does this sound like to you... Thankyou very much.

PS: I have no pain, no blurriness, no blood-shot, no pupil dilation issues etc. I do dry eyes (diagnosed dry-eyes, not just guessing).

[JohnHaganMD]

As I hope you know white light is made up of the full color spectrum and anything (glasses, contacts, human cornea, rain, atmosphere, mirror, prism, light-bulbs, etc) can diffract the light such that we see colors.  Since multiple people saw it no need to consider intrinsic eye disease and pass it off to diffraction of light.  Why some lights and not others? Multiple variables including ambient light, nature of light source, angle and material the bulb and fixtures are made of.

[MojaveNick]

Thankyou that's cured my paranoia.. but I don't understand what's the difference between 'norm' and 'abnormal', is the rainbow constantly there at every angle, intensely obvious etc on every single light, how come people on google don't ever talk about diffraction etc, or is what I'm becoming aware of just general knowledge?

[JohnHaganMD]

Rainbow's cannot be seen by everyone in a given city or area. If you are really interested read the sections on wikipedia.com  on diffraction or light spectrum or even 'why do we see rainbows"     If the earth were not in the way and conditions were optimal a rainbow would be a 360 circle.  When I was flying in a glider in Hawaii I saw a 360 degree rainbow.