RE: Effects of lens implants on color vision (Was RE: Human color vision)
RE: Effects of lens implants on color vision (Was RE: Human color vision)
- Subject: RE: Effects of lens implants on color vision (Was RE: Human color vision)
- From: Wayne Bretl via colorsync-users <email@hidden>
- Date: Wed, 15 Jan 2020 17:37:06 -0700
Here's my "organ recital," all about my visual organs:
In my youth, my acuity was considerably better than 20/20. I could recognize
a very tiny astigmatism in my right eye when looking at the horizontal and
vertical slats on air vents across the gymnasium. Run-of-the-mill vision
tests didn't go to that extreme. I was an example of the joke where the doc
says "Read the last line" and the answer is "Printed by local union 71."
Both of my eyes are 20/20 now, but my left eye got there through a long
chain of events.
Years before cataract surgery, I got a small foreign body in my left eye. My
primary physician found it, but didn't tumble to the fact that it had
promoted iritis. The irritation got worse and worse over a period of a few
days, and in the resulting visit to an ophthalmologist I was prescribed some
extra-strength drops (a type of cortisone? I don't recall) with the
unfortunate side effect of promoting a cataract. My (years) later
ophthalmologist was very conservative about doing cataract surgery before it
was absolutely necessary, and I think she waited too long. I had repeatedly
asked for it, but she talked me out of it until I told her I couldn't pursue
my electronics hobby because my depth perception was too poor to solder
wires (getting the wires, solder, and iron to meet at the same distance.)
During surgery (2009), the natural lens broke out of the capsule and chunks
went into the vitreous. This required implanting a lens in front of the iris
(which is kept at the ready for cases like this), and a vitrectomy within a
week. During the vitrectomy, they also laser welded my retina in place as a
precaution. I can sometimes see the weld points as very briefly visible
points of light when suddenly turning on the lights in a dark room. After
the vitrectomy healed (on the order of a month or more, instead of the few
days for a successful cataract surgery), I also got a laser iridotomy to
prevent pressure buildup in the eye due to possible blockage by the anterior
implant.
If you look closely at my left eye, you can see the implant in front of the
iris. I have noticed a reduced speed of adaption to extreme light level
changes in this eye (being "dazzled" for a minute when going into the
sunlight, and longer adaptation time to the dark), but no other deficit.
The right eye surgery was done in an earlier stage of cataract progression,
by a different doctor who was not so hesitant, and went perfectly.
Picking the right diopter implant is difficult, both because of errors in
measurement with the cataract in place and because the shape of the eye
changes after surgery. I asked for distant vision in both eyes, since I was
used to progressive bifocals anyway, but ended up with best focus at
computer monitor viewing distance. It is not so far off that I am required
to have glasses to drive. After successful surgery, I was able to return to
my role as "golden eyeball" for video quality and coding artifact assessment
in my work.
-----Original Message-----
From: colorsync-users
<colorsync-users-bounces+waynebretl=email@hidden> On Behalf Of
Wire ~ via colorsync-users
Sent: Wednesday, January 15, 2020 4:34 PM
To: 'colorsync-users?lists.apple.com' List <email@hidden>
Subject: Re: Effects of lens implants on color vision (Was RE: Human color
vision)
Re UV coatings, I think that's distinct from anti-reflective coatings, a
cheaper form of which produce the very striking blue reflection that some
people find fashionable.
Re cataracts, I've often heard of a link between UV exposure and cataracts.
But like everything I found it's more complex... I developed a condition
where as the eyeball changes shape due to elongation from muscle strain of
strong distance correction for near field viewing (eg computer displays) the
jelly in the eye separates from the retina and creates a horrible crippling
form of floaters. For aging suffers of diabetic retinopathy (my late father)
there's a treatment of replacing the vitreous jelly with saline and this can
cure the problem as a nice side effect of the treatment. But it's been found
that vitreous jelly has a critical effect inhibiting cataracts, and that you
are guaranteed to require lens replacement within 5 years after a
vitrectomy. The Doc said there is some science that suggests that its oxygen
impermeability of the jelly, or rather it's permeability, that's crucial to
the onset of the disease.
Wonders...
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