Light coloured Eyes and the sun

[cougie uk]

Hmm, but it’s the size of the pupil that determines how much light reaches your optical nerve, not the iris?🧐

Apparently it is true. I had to Google. Well I never!

 

[Mad Doug Biker]

Apparently it is true. I had to Google. Well I never!

There is a reason why brown is the most common eye colour, especially in hot and sunny countries. Also things like skin and hair colour too.

Hmm, but it’s the size of the pupil that determines how much light reaches your optical nerve, not the iris?🧐

But if you know how a lens works, in bright light, the eye is 'stopped down', so the iris, the coloured bit or the diaphragm surrounding a lens aperture so to speak, will, or probably will, be quite prominent as your pupils, the apertures, are smaller.

Darker eyes also tend to be less sensitive to light (although not always, I'm sure).

 

[Mad Doug Biker]

Apparently people with lighter eyes are more prone to cancers of the eye called Uveal Melanoma. This is caused by the eye not being able to protect itself as easily from light.

If you have blue or green eyes, you are genetically more likely to have a higher alcohol tolerance and drink problems.
Also, people with lighter eyes can adjust their vision from dark to light (or vice versa) more quickly as their eyes are more sensitive.

People with brown eyes are more susceptible to Seasonal Affective Disorder, or SAD, as the eye needs more light due to it being less sensitive. Or something.

 

[mistyoptic]

Apparently people with lighter eyes are more prone to cancers of the eye called Uveal Melanoma. This is caused by the eye not being able to protect itself as easily from light.

If you have blue or green eyes, you are genetically more likely to have a higher alcohol tolerance and drink problems.
Also, people with lighter eyes can adjust their vision from dark to light (or vice versa) more quickly as their eyes are more sensitive.

People with brown eyes are more susceptible to Seasonal Affective Disorder, or SAD, as the eye needs more light due to it being less sensitive. Or something.

Also more at risk from macular degeneration which is far more common. Even more reason to wear good UV protective specs/sun specs

 

[Regular.Cyclist]

I have grey eyes, though they appear to change to blue or green depending on ambient lighting conditions. I need to wear sunglasses in bright light and use transition lenses in 90% of my cycling glasses.

I was told, at an eye test around 7 years ago, that there was signs of snowflake cataracts in both eyes, something that wasn’t present at the previous eye test. It has not developed since and I put some of that down to my use of sunglasses.

 

[Ming the Merciless]

But if you know how a lens works

Just about anyone over the age of 10 🙄 it must mean more light is getting through the lighter coloured Iris to hit the optical nerve

 

[Mad Doug Biker]

Just about anyone over the age of 10 🙄 it must mean more light is getting through the lighter coloured Iris to hit the optical nerve

There is that too, there are less layers of melanin/pigment, etc, so yes, colour does matter!

However, I said what I said about lenses because clearly nobody would be walking about in bright sunshine with eyes at the equivalent of f2.8, (or similar. Exaggeration, I know) with little to no iris visible, regardless of eye colour, so, given with the colour thing above, it isn't as simple as you made out about light hitting the optic nerve in a uniform way, everyone is different, hence the reminder of how a lens/eye works.

 

[Ming the Merciless]

There is that too, there are less layers of melanin/pigment, etc, so yes, colour does matter!

However, I said what I said about lenses because clearly nobody would be walking about in bright sunshine with eyes at the equivalent of f2.8, (or similar) regardless of eye colour, so, given with the colour thing above, it isn't as simple as you made out about light hitting the optic nerve in a uniform way, everyone is different, hence the reminder of how a lens/eye works.

But everyone’s iris would contract to reduce the pupil size. What does that have to do with eye colour, does a darker iris mean the pupil diameter is smaller under the same light conditions?

What we are trying to get at, is why does a lighter iris make an eye more sensitive to light?

 

[Mad Doug Biker]

But everyone’s iris would contract to reduce the pupil size. What does that have to do with eye colour, does a darker iris mean the pupil diameter is smaller under the same light conditions?

I don't think so, a darker eye merely has more pigment and so on to absorb/deflect light

What we are trying to get at, is why does a lighter iris make an eye more sensitive to light?

You actually said it yourself earlier, the iris in a lighter eye has less layers, so more light gets through 'the edges' so to speak. Why this is, I don't know, I mean, you'd think a lighter colour would be more reflective, but, eh, I didn't invent the eye.

The point I was trying to make is that there is a connection with eye colour due to anatomy, etc and it isn't the same for everyone

 

[Mad Doug Biker]

What we are trying to get at, is why does a lighter iris make an eye more sensitive to light?

I can but imagine that given the prevalence of lighter coloured eyes in northern latitudes, that they evolved to deal better with darker light, after all, in the middle of a drab British winter or somewhere further north, like Norway, it would seem advantageous. Maybe that is why the layers of a lighter coloured eye are less protective and they let more light in?

This of course doesn't seem to factor in things like snow, mainly in northern countries, unless I am missing something (most likely, I am no Optometrist).

It would appear that lighter eyes are less efficient compared to dark eyes, but they have clearly evolved for different purposes.

 

[oldwheels]

I never used to wear sunglasses but had a pair in my van which I had to use when driving in bright sunshine with lying snow. Just as well I had them as I would not have been able to drive safely otherwise.
Having had two cataracts done I now have to wear them in any bright conditions when driving or cycling.
On the trike you are facing upwards a bit more than on two wheels so more vulnerable perhaps.
Age degeneration may have some influence.

 

[Bonefish Blues]

But everyone’s iris would contract to reduce the pupil size. What does that have to do with eye colour, does a darker iris mean the pupil diameter is smaller under the same light conditions?

What we are trying to get at, is why does a lighter iris make an eye more sensitive to light?

Searched your query using your term.

https://www.milaneyecenter.com/reso...hits a lighter,in even more light sensitivity.

I have dark eyes and am able use a much lighter tint than others when fishing.

 

[fossyant]

Remembered the sunglasses today. Much better, but avoded the worst of the sun, and came inside early afternoon, then went for a walk away from the pool.

 

[DRM]

I don't have any sun

 

[DRM]

I have several pairs of sunglasses, in the car some Ray Bans, and if it's very bright some O'Neill blue mirrored polarised sunglasses, aimed at watersports, they really are excellent, even saving the day when the low glare from the sun obscured the A64 near Malton, I was able to see enough to avoid the 3 cars that flew past me, then ran into each other, not bad for £14 at TK Maxx, for the bike some Oakley Sutro T de F special editions, £69 at TK Maxx, being blue eyed bright light does seem to cause discomfort