Color blindness, day blindness, and good night vision may have something to do with the normal or abnormal operation of the rods & cones in your retina.


The eye perceives color using the "cones," cells in the retina named after their shape. If I remember my physiology correctly--and someone step on my foot if I don't--there are red/green cones and blue/yellow cones. Red/green color blindness is most common, blue/yellow less common, and complete color blindness least common of all.


Brightness without color is sensed by the rods. We rely on the rods for night vision, and I believe that rods outnumber cones towards the edge of sensing portion of the retina. I believe that with the rods one may actually have better visual acuity. Motion detection also depends more on rods than cones. (again, I could be getting this only half right, but this is what I recall.)

as to having your vision "saturate" during the day, i'm not sure what the cause may be. I'd guess that your pupils are too wide open, which may be a problem of the brain misreading the intensity of ambient light. Other than that my only guesses would be that your cones & rods are more sensitive to light than those of other people, but i'm not even sure how much sensitivity can vary. There are eyedrops to dilate (widen) the pupils, but i'm not sure if there are eyedrops to constrict them. In any cases the pupils need to respond very quickly to changes in light levels, and they're much better at this than your typical video camera.


You may already wear dark sunglasses or dark wraparound sunglasses during the day to compensate. If not, consult an optometrist about the wisdom of doing so. By wearing sunglasses your pupils are likely to widen to compensate. Be certain to wear sunglasses with lenses made from polycarbonate or from some other material that blocks 99% of uv-a and uv-b light.


In software it's a simple matter to convert a color image (or color video) to black & white, but i'm not aware of any material that can do this to light.


For more info on this and other subjects, check out the open source online encyclopeida wikipedia .


- gary

Thanks for the reply.

I do wear my sunglasses a lot when I drive now, I just can't stand squinting anymore.

I should probably go to an optamitrist one day, its been about 10 years since i've been to one.

I'm kind of disappointed that the 2 conditions aren't related. I wish it was just a problem with the cones or the rods, not both. Oh well. I've got good eyesight so I don't care having horrible day vision or loss fo colour. The day blindness isn't extreamly bad, but enough that it forces me to squint whenever i'm outside on a clear day.

Here's a wacky idea:

is there any chance you could get tinted contact lenses? I'm not sure if it's possible or even safe, but it's a thought.

Ideas less wacky:

rather than seeing an optometrist, you may wish to see an ophthalmologist, especially if you haven't had an exam for a decade. I'm certain that with a little searching you could find someone who has studied and perhaps even treated your condition.

The difference in brightness between a bright, sunny day and the indoors is greater than we usually perceive it to be since the pupil adjusts very quickly. Perhaps there's a "ceiling" to the brightness you can tolerate without sunglasses, and you hit this ceiling only on sunny days and perhaps (?) when you look into very bright lights.

Good luck to you.

- gary

What type of colour vision defect do you have?

Are you extremely sensitive to the light or is it just an annoyance?

You have three types of cones. They respond maximally to short, medium, and long wavelength light. They respond maximally in high lighting conditions (ex daytime). These are the receptors that are affected in colour vision defects. Typically, one of the receptor types is deficient or missing giving rise to one of three colour vision defects (commonly known as red/green or blue/yellow). Usually the missing/deficient receptor is replaced by one of the other types thus it does not normally affect your light sensitivity just your perception of colour, except in severe defects.

You also have rods, which respond maximally in low lighting conditions. These are not responsible for your colour vision hence your night vision is unaffected. These receptors saturate in high lighting conditions.

There is complex interplay and inhibition between these two pathways. But, unless your colour vision is severely affected (pretty much see in greyscale) this shouldn't be the reason for your light sensitivity. Some people are just more sensitive than others.

I would suggest a good pair of sunlasses, unless you have a severe defect in which case different filters would be beneficial.

Hope this helps.

Ps. Don't hesitate to see the optometrist if this bothers you -- they are trained to, and do, deal with these types of problems all the time.

It depends on whether it is merly an annoyance or actually extreamly sensitive. Most of the time its just an annoyance, but tehre are days where its actually painfull to go outside without squinting, especially in the winter or when i'm kayaking. Now that I have done a little more research on the topic I think I am just overly sensitive to light. Not enough to really considered a condition, but enough that it does get annoying. It is actually beneficial in a way because as I said before I have excellent night vision, and i'm also an amateur astronomer so its great for that.

As for the colourblindess type, I think (i've never been formally diagnosted by an optomitrist) I have protanomaly, which is red-weakness. I am thinking of going to an optomitrist soon to ask about the colour blindness. It has started to affect my university work. Colour coded maps are becoming dreadfully evil to try and read, and my geology labs are suffering.