This may seem crazy, but blue irises are not actually pigmented blue. They
are non-pigmented. The blue color is due to the Tyndall effect (light
scattering). See this:https://www.aao.org/eye-health/tips-prevention/your-blue-eyes-arent-really-blue
Those with brown eyes have melanin pigment in their irises, so they are
actually brown in color.
There is some evidence that those with blue eyes are more light sensitive
overall, and light may not only scatter, but may pass through even the part
of the iris that is “closed” (i.e., not the pupil) because there is no
pigment to absorb as much light. I know two people, both men with blue
eyes, who claimed to have increased sensitivity to blue light and were
bothered by the blue lights that are sometimes used to indicate the
location of emergency call boxes. I was with them on more than one occasion
when they would shield their eyes from blue light sources (those call box
lights, blue neon signs, blue flashing emergency lights, etc). I never did
understand why they had this, but this article (oriented to
ophthalmologists and other physicians) discusses some of this as well as
the relationship with migraines and the possible causes:https://www.aao.org/eyenet/article/md-roundtable-solving-photophobia-puzzle
Maybe that lack of iris pigment?
I hope the information is useful.
Steve Horii (I am a physician, but not an ophthalmologist)
On Sun, May 23, 2021 at 19:35 Mark Vincent <email@example.com>
I would like to know from anyone in this group that has a good educated to
known medical reason why I have a higher sensitivity and ease of viewing
light that is blue to violet so easily. I understand the rods and cones in
the eye and have enough medical knowledge to understand the Latin and Greek
terms of medical words. I have NO problem in seeing, focusing or any form
of eye strain on light that is in the high frequency part of the spectrum
of blue to violet, including indigo. I have always been this way. One note,
I do have blue eyes if that makes any difference. They are not the striking
steel blue that can look like blue lasers. Jean Harlow had steel blue eyes,
as an example of someone. Blue/ steel blue eyes in a male is far more
common in a male than a female.
Another thing I have with my eyes is that under 50/60 c/s flicker, I will
get a severe migraine and have the vision of "Mr. Magoo" within a few
minutes that takes a few hours to wear off after being removed from the
flickering light(s). For reading and general lighting, I prefer carbon
filament (Ferrowatt). Tungsten is fine.
Brenda mentioned having a RM565 scope with a blue trace (must be P11 by the
model) that she gets eye strain easily. This is what finally made me ask
the group this. Others have mentioned how P11, blue, is nice briefly, not
for any time without the owner having eye strain and hard to focus on. I
have seen older posts on this group and other places online about people
saying blue trace is nice but annoyed by the hard to focus on and eye
strain within a few minutes. I have a couple of friends with blue eyes that
I asked about blue-violet phosphour. They said it is nice to glance at or
for a short time, not for any longer. They said they would prefer P1, P31,
etc, that is in the green area to look at for any length of time, a minute
or more. I will deal with P1 or P31. I find P2 the WORST to look at. The
blue part is fine, the cyan afterglow I find bilious. P7 is not as bad as
the afterglow is yellow with only the blue seen with a proper filter. Even
so, I will keep the intensity of a P7 low so as to only see the blue.
I know storage types need a P31 because of the secondary emission.
Something like the 2467/B or 7104 with the MCP could have been made with
other phosphours when made. The MCP does not care about the phosphour, only
acting like a photomultiplier.
I would like to find the P11 crts for my 556, 7603 and 465. The P31s in
them are in very good condition. I prefer the P11 because of the thinner
trace, ease on my eyes. and faster decay time. To find a 502A with P11 and
T317P11 for my 317 would be great. I know the 502A is 2mc capacity. The
7000 series I have, except for the 7934 and 7104, now have the P11 in them.
I do have good P31 types I removed from the scopes sitting around. I do
have a few of the 300, 400 and 500 series with the P11. If I can find
someone who can successfully rewind the high voltage transformers for the
older types, I would really like P11 for me 545B and 547 after getting
these transformers rewound. The only thing I have seen P16 in is a B&K 1076
analyst. That colour does not bother me at all. So far I have not seen a P5
although having any of these, 3AP5 for example, in place of a P1 would be
great. I know the decay time and light output of P5 is less and P11.
For any plant that has flowers, I do not mind any colour.