Why do we see blotches after looking at lights?

13 March 2011



Why is it that when you look into any type of light for a long period of time that blotches of black appear when you look away?


Sarah - Well this is very similar to the effect that you get when you're standing there at a party and someone takes a photo, and you get those spots in front of your eyes from the flashes and you just can't see anything.

It's because of something called photo-bleaching and it happens to the cells in your retina which is the light sensitive bit at the back of your eye. It's populated with cells called rods and cones, and these are full of light sensitive pigments.

Normally you get light as particles called photons coming into your eye; these stimulate the cells by changing this light sensitive pigment, which is called retinal, into a slightly different form and they stimulate the cells to send electrical impulses to your brain.

But, if you get a really bright light - like a flash or if you look at the sun for a long time or even just a really bright light bulb - this sends the cells into overdrive and they get really overexcited, and it takes them a little while to calm down. So then when you look at a normal level of light, like a wall, you get these kind of black spots where you've been looking at light where the cells have been over stimulated.

Chris - So, you have lost the photo pigment in that particular area temporarily because it's been broken down by the photons of light hitting it, and when it regenerates, it comes back then you see normal again, but while it's regenerating up the pigment because of the overexposure, you see a less intense spot, so you therefore see a dark spot. It's worth noting actually that the retina is less active when light shines on it than in the dark. It's in fact deactivated by light rather than activated by light. It's rather paradoxical, isn't it?

[Note added in proof - you should never look directly at the Sun. The lens in your eye focuses light onto the retina in the same way that a magnifying glass can focus the Sun's rays to a spot and cause things to burn. You can burn a hole in your retina leading to permanent sight loss...]


when i look into bright light such as light bulb or flash lights..etc i seeing the shape of the object(light bulb) in reddish yellow sometimes in green color .if i look into sun i see reddish yellow round shape these shapes are longer for 1 or 2 minutes. i also have floatres in my vision and have litle blur vision and ima using specs .

When ever I happen to look into a bright light by accident like my desk lamp or even the break lights from cars, its like it gets burned into my retina really quickly and its like i see splotches, usually like a royal blue. it only last for maximum a few minutes. I just turned 20 and this has been happening for a few years. I just went to the ophthalmologist a few months ago for a scratched cornea. I didn't mention anything about the splotches but he looked directly into my eyes and did a thorough exam and he said everything looks great. would he have noticed if anything was wrong at the time? should i be worried? I have severe hypochondriac anxiety.

You shouldn't worry about that because your retina regenerates. So, after some time those splotches disappear and your eye is back to normal-ish.
But still, try to avoid looking directly into bright lights because long exposure can lead to permanent damage.

With regard to this comment above:

"You shouldn't worry about that because your retina regenerates."

This is totally wrong. In some animals the retina can regenerate, but not in us. If you damage your retina the injury will be permanent. This is why people develop sight-loss disorders like macular degeneration.

Scientists are actively pursuing techniques for the use of stem cells to regenerate retinal structures, but this process does not have spontaneously.

Please be careful with your eyes...

My brother got a laser pointer for his birthday and shone it in my eyes >:( Most of the dark areas faded within 30 mins, but 14 hours later there are still 3 little dots I can see in my right eye. they are a pale grey colour and are opaque. the apear 4mm(s) in diameter (each) at 1m away. Should I be concerned or just wait a little longer?
Yours Sincerely,
Fred H.

Persistent blind spots 14h after the laser exposure is worrying; I think you should seek specialist advice.

This only happens at night. If I'm driving and an emergency vehicle passes with their lights (blue, white, red) I see neon purple when I look away. It's always a bright purple and it last for a while. Obviously I need to get an exam, but I'm nervous. And no, I don't use drugs if that crossed anyone's mind, haha.

My eye sight is seeing blotches of spots and seeing things that arent really there and faces in the clouds is that due to the sun when it comes out and its so bright that it knows where to know where im at its always looking for me or at me i look bk at it i think it messed up my retnia can u help

I was making a video and used the selfi mode to video my face and such. I did not realise that doing this triggered the flashlight feature, I looked away and turned it off. I then tested out with settings and used selfie mode again, aimed away from my eyes. I'd say that I probably only looked for a few seconds and certainly looked away via blink reflex. Scouring the internet hearing about LED eye damage, quite scared. I did see a darkish line for a moment that then dussapeared, my eyes feel slightly uncomfortable and watery. However as far as I can tell, my eyes are okay. I notice slight blueishness when looking around, but I think that is more of an afterimage effect fromy my phone screen. I should note that I suffer with extreme ocd, particularly about vision, so a prompt reply would be extremely appreciated.

It seems pretty fine, just a result of an accident. But I would still recommend seeing an eye doctor, one you can get to a little quicker, if the problems persist. Even if your eyes feel just a little uncomfortable afterward, let’s say more than 12 hours later, then please go see a specialist.

I know this has nothing to do with the blotches of light, but if I move my eye to the corner, it moves itself across it until the middle

for some reason,i always see pixels and this has been going on for years. as in barely noticeable slightly dimmed teeny tiny circles.And when i look at one of my walls from far away my eyes just see well,the wall.But when i get close up it sees the tiny little circle hills. should i get glasses?

I have this as well. For me it is something that I've noticed people have a hard time believing when you explain it to them. Most doctors aren't even aware of it because it is rare. Its a condition called visual snow or visual static. I'm no expert on the subject but from what I've read there isn't a lot in terms of scientific explanation. I find it interesting that they would go away the closer you get to a wall. for me they basically stay the same. I haven't looked all over for info but clearly from the bit of research I've done (really just googling) there isn't too much research on it. People who have this condition usually have migraines as well but those don't happen to me more then maybe twice a year. Wikipedia has some useful info as well. hope this helps.

If I look at a light or something for a few seconds I see dots of green. Why is that?

That's weird it's the same for me

how Long is it supposed to last when you see blotches

Same thing as what they said, you are just experiencing a different shade, maybe to do with amount of light.

Is it normal to see dots when looking at bright lights or car lights at night and how to prevent it. Do you think sunglasses will help with cardboard stuck at the side or is there something i can get to help this problem.

I was washing an eyelash out of my eye and I rub my alot I also was shining a flashlight in my eye to make sure it was out of my eye.
Now I see slight dark spots my eyes are open and White Lines when my eyes are closed; how long will this last? It's been about 5 it's also 3 in the morning should I go to a doctor am I okay?

Can you help

When i look at something bright or like the sun shines on a windshield and I look at it and then about ten minutes later the right corner of my eye go's black and I can't see anything on my right side and it last about 15 minutes and then go's away then I get a real bad headache what could be the cause of that.

Me too. I had to stop driving .Every time I see a reflection off a car I cant see. I cant even walk far in a parking lot . I lost my sight if I see a reflection in seconds. I try my best not to look at cars when the suns out but its really hard to look down all the time when your walking.

I am 17 years old. Once I saw at my phone's flash light and then I felt like the light traveling through my brain nerves. And then I am getting very slight pain begging my eyes. Anything serious....

Lately, this has been happening to me when I stare at normal stuff like if I'm staring at a white wall and my teacher, there will be an outline of my teacher. Are my eyes broken?

This is normal, Amy. Staring at anything for an extended period leaves a temporary "imprint" on the retina; this is because different visual pigments are consumed in different proportions in different areas of the retina. Then, when you look away or fixate on something else, the sensitivity of the retina to certain colours is momentarily altered, making a ghost imprint of what you were seeing before appear before your eyes. It should disappear in a few seconds.

What it sounds like you have is either persistant migraine aura that can cause palinopsia. It's Greek for "seeing again" I have had it for a year. From what j know it's to do with hyper excitability of the visual cortex. I'm on medication for it just now

Hey does this have a name? Not the scientific reasoning I mean when you look at light and you see blotches, does that experience have a name?

Hello, I am a structural steel welder, and it's not uncommon for me to spend a full 8 hour day under my welding mask. I always try and use the darkest shade possible to protect my eyes from the arc flash, but even then when I lift my hood and blink a couple of times, I will still see a small dark spot right in the middle of my vision where the arc of the weld is the brightest through the lens...

It worries me because I feel like that can't be good for my eyes...but I don't really know of anyway to stop from happening.

When our light sensing cells get over stimulated like that, is it hurting them?

I'm sorry I really do not know, perhaps talk to an optimoligiest or try to get a better coverage with your shade on your mask. Good luck!

So I as a joke stared into the sun for like a minute tops but didn't really squint my eyes and afterwards I got the usual side effect where there is blotches of light in my vision but this has lasted a few days now instead of a few minutes and im getting a tad worried, should I be worried or will this go away in some time?

I would scurry over to an optometrist and get my eyes checked. Anything more than a few days could be a worrying sign.

You should seee this a doctor or maybe not to do that again

There is always a fix for the retina and the eyes, we are in a generation where the doctors and eye surgens can put the retina back into its original place so if you ever go blind, you may bot be blind forever

Therapies to restore the retina are in their infancy. Sightloss secondary to retinal degeneration is common and currently permanent. What you have written above is totally wrong.

If I look at a light or something for a few seconds I see dots of green. Why is that?

You answered your own question, you see those dots because you looked at a light to bright for your eyes, and so dots in your vision is the effects of someone being stubborn and for some stupid reason they looked at a bright light for to long

I have noticed that lately if I have been looking at my phone screen or computer screen for a while and then I look away from it everything is kinda colorful and splotchy. But then after about 5 minutes or so everything is back to normal. Why is that?

Thats normal. Try moving your phone / pc screen away from your eyes and take 1 minute breaka every 20-30 minutes. Also, try to work in natural light.

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