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Albinism and reduction of high definition receptiors
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Scott Seidman
medicine forum Guru Wannabe


Joined: 04 May 2005
Posts: 235

PostPosted: Mon Jul 10, 2006 12:57 pm    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

"Adrian Parker" <nospam@nospam.com> wrote in
news:kqzrg.281820$8W1.85184@fe1.news.blueyonder.co.uk:

Quote:
I've been having neurofeedback to
correct the nystagmus and it has helped for near sight, but not long
distance, and I'm wondering if it is because of the fine receptors not
being able to resolve down to a small enough resolution.


There are a variety of methods used to decrease the congenital nystagmus
associated with albinism, and there success rates usually correlate to how
well you could see if the nystagmus isn't there.

An inexpensive approach that might work real well and doesn't require any
training or repeated visits and such is simple base out prisms, with an
extra -1 cut in to account for the increased accomodation at far.

--
Scott
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biscuit
medicine forum Guru Wannabe


Joined: 24 Apr 2005
Posts: 296

PostPosted: Sun Jul 09, 2006 9:55 pm    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

Many thanks !

"Dr Judy" <mpace99@rogers.com> wrote in message
news:1152412314.567660.29770@m79g2000cwm.googlegroups.com...
|
| Adrian Parker wrote:
| > Hi,
| >
| > I've been told that in the eye of a person with albinism, there are
fewer
| > rods to 'see' fine detail of an image. So even if all the other eye
| > conditions were corrected, there would still be a problem seeing.
| >
| > Does anyone know what % the reduction of Rods is as compared to a normal
eye
| > ?
| >
| > --
| > Adrian Parker
|
|
| Don't know the percentage, don't know if has been calculated. In any
| case, it will vary from individual to individual depending upon the
| type and severity of the albinism.
|
| It isn't actually rods that are reduced and rods are not responsible
| for fine detail, cones are. In albinism, the retinal pigment
| epithelium (RPE) is very thin or missing, since it is a pigmented
| tissue and pigment is what people with albinism lack. The RPE supports
| the photoreceptors, both rods and cones, and when it is lacking then
| the photoreceptors either don't develop or develop poorly. Fine
| detail is lacking because the cones in the macula, the most detail
| senstive part of the retina, are lacking or defective. So yes, even if
| other conditions like strabismus or refractive error are corrected, the
| malfunctioning photo receptors means that acuity will be reduced.
|
| The lack of good quality central vision often causes nystagmus as the
| eye searches for the lacking crisp spot, provides less of a stimulus to
| fusion so strabismus is common with albinism and interferes with the
| emmetropization process so that high refractive error is common with
| albinism.
|
| For more info, see
|
| http://www.revoptom.com/handbook/SECT58a.HTM
|
| Dr Judy
|
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Dr Judy
medicine forum Guru


Joined: 07 May 2005
Posts: 304

PostPosted: Sun Jul 09, 2006 2:31 am    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

Adrian Parker wrote:
Quote:
Hi,

I've been told that in the eye of a person with albinism, there are fewer
rods to 'see' fine detail of an image. So even if all the other eye
conditions were corrected, there would still be a problem seeing.

Does anyone know what % the reduction of Rods is as compared to a normal eye
?

--
Adrian Parker


Don't know the percentage, don't know if has been calculated. In any
case, it will vary from individual to individual depending upon the
type and severity of the albinism.

It isn't actually rods that are reduced and rods are not responsible
for fine detail, cones are. In albinism, the retinal pigment
epithelium (RPE) is very thin or missing, since it is a pigmented
tissue and pigment is what people with albinism lack. The RPE supports
the photoreceptors, both rods and cones, and when it is lacking then
the photoreceptors either don't develop or develop poorly. Fine
detail is lacking because the cones in the macula, the most detail
senstive part of the retina, are lacking or defective. So yes, even if
other conditions like strabismus or refractive error are corrected, the
malfunctioning photo receptors means that acuity will be reduced.

The lack of good quality central vision often causes nystagmus as the
eye searches for the lacking crisp spot, provides less of a stimulus to
fusion so strabismus is common with albinism and interferes with the
emmetropization process so that high refractive error is common with
albinism.

For more info, see

http://www.revoptom.com/handbook/SECT58a.HTM

Dr Judy
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Mike Tyner
medicine forum Guru


Joined: 24 Mar 2005
Posts: 1299

PostPosted: Sun Jul 09, 2006 1:39 am    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

"Charles" <nospam@nospam.com> wrote

Quote:
exclusively villains... for what it's worth, when I was a kid I was
addicted to a fantasy book series in which the hero/main character was
albino. Wink

Reminds me of a favorite Dean Koontz character, from Sieze The Night. -

"'The night is a kingdom of predators, in which every hunter is also the
hunted.' The night is also the favored realm of Christopher Snow, whose XP
(xeroderma pigmentosum) renders him extremely vulnerable to all forms of
light. When an old flame's son is abducted, Snow and his faithful dog Orson
track them to Fort Wyvern, an abandoned military base--and the site of
genetic research experiments gone awry. To recover the boy, Snow and his
friends must unearth Wyvern's darkest secrets. .. Though long, Seize the
Night will certainly hold your interest. (Running time: 12 hours, 10
cassettes)"

-MT
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biscuit
medicine forum Guru Wannabe


Joined: 24 Apr 2005
Posts: 296

PostPosted: Sat Jul 08, 2006 9:54 pm    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

Until I saw your post (and followed up with some Googling) I didn't
realize that albinism so frequently caused (or came along with) poor
vision. One site I read pointed out how albino characters are almost
exclusively villains... for what it's worth, when I was a kid I was
addicted to a fantasy book series in which the hero/main character was
albino. ;)

Best of luck.

Adrian Parker wrote:

Quote:
I did get the idea that he wasn't a professional when he asked about
how I see, hence I gave an explanation of all that is occurring.. as
I believe that the more people who understand the visual problems
people have, the better Smile Albinism in particular is a very
misunderstood and often vilified condition (take the da vinci code
file for example).


--
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biscuit
medicine forum Guru Wannabe


Joined: 24 Apr 2005
Posts: 296

PostPosted: Sat Jul 08, 2006 9:32 pm    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

I did get the idea that he wasn't a professional when he asked about how I
see, hence I gave an explanation of all that is occurring.. as I believe
that the more people who understand the visual problems people have, the
better Smile Albinism in particular is a very misunderstood and often
vilified condition (take the da vinci code file for example).

"Charles" <nospam@nospam.com> wrote in message
news:UzNrg.25617$FQ1.2358@attbi_s71...
| Adrian,
|
| Ace is just a kid who spends too much time on the computer. I'm sorry
| that he has hijacked the thread and no credible people have yet
| replied. I just wanted to warn you, and hopefully someone
| knowledgeable will give you a good response.
|
| Adrian Parker wrote:
|
| >
| > <acemanvx@yahoo.com> wrote in message
| > news:1152319937.412885.241340@b28g2000cwb.googlegroups.com...
| > > Ah I see. I will do more research on that. Do you see the world
| > > pixelized with anisometropia blurring? Can you describe what you
| > > see exactly?
| >
| > With albinism, there are several other factors that affect vision:-
| > Nystagmus, Astigmatism, Photophobia, Squint and Strabismus.
| >
| > I'm told that when I squint, it adversely affects the vision centres
| > of the brain, so I've been working on reducing that.
| >
| > Nystagmus.. causes a problem because the brain has to snapshot images
| > instead of getting constant updates, so for a moving target, I'd see
| > less detail than a normal sighted person because of what is probably
| > like a strobing effect, you see the movement, but your brain only
| > gets images now and then and so has to fill in the gaps with a best
| > guess.
| >
| > Astigmatism.. in my case, my last eye test gave me figures of
| > Right Eye : Sph +7 Cyl -4 Axis 15
| > Left Eye : Sph +6 Cyl -2 Axis 175
| > So, as you can see, I need quite a high corrective lens, so my eyes
| > are trying to compensate for the imprecise nature of the lenses.
| >
| > Photophobia.. this causes me to squint, so I have to ensure I wear a
| > brimmed hat and dark glasses outside else I have to squint a lot.
| >
| > Strabismus.. With the treatment I've been having, this seems to have
| > been reduced quite a bit, my eyes are far more convergent than they
| > used to be, and my binocularity seems much improved.
| >
| > So, to describe what I see compared to a normal sighted person has to
| > take into account several factors, including how tired my eyes are,
| > or how stressed I am (stress affects nystagmus a lot). I do not see
| > the world moving from side to side because of my congenital nystamus
| > as my brain edits it out, nor do I see the world as a blur (like in
| > your image), I see a clear picture, but like you, when you look at a
| > very distant object, you can see it ok and it isn't blurred, you just
| > can't make out fine detail.
|
|
|
| --
|
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biscuit
medicine forum Guru Wannabe


Joined: 24 Apr 2005
Posts: 296

PostPosted: Sat Jul 08, 2006 12:30 pm    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

Adrian,

Ace is just a kid who spends too much time on the computer. I'm sorry
that he has hijacked the thread and no credible people have yet
replied. I just wanted to warn you, and hopefully someone
knowledgeable will give you a good response.

Adrian Parker wrote:

Quote:

acemanvx@yahoo.com> wrote in message
news:1152319937.412885.241340@b28g2000cwb.googlegroups.com...
Ah I see. I will do more research on that. Do you see the world
pixelized with anisometropia blurring? Can you describe what you
see exactly?

With albinism, there are several other factors that affect vision:-
Nystagmus, Astigmatism, Photophobia, Squint and Strabismus.

I'm told that when I squint, it adversely affects the vision centres
of the brain, so I've been working on reducing that.

Nystagmus.. causes a problem because the brain has to snapshot images
instead of getting constant updates, so for a moving target, I'd see
less detail than a normal sighted person because of what is probably
like a strobing effect, you see the movement, but your brain only
gets images now and then and so has to fill in the gaps with a best
guess.

Astigmatism.. in my case, my last eye test gave me figures of
Right Eye : Sph +7 Cyl -4 Axis 15
Left Eye : Sph +6 Cyl -2 Axis 175
So, as you can see, I need quite a high corrective lens, so my eyes
are trying to compensate for the imprecise nature of the lenses.

Photophobia.. this causes me to squint, so I have to ensure I wear a
brimmed hat and dark glasses outside else I have to squint a lot.

Strabismus.. With the treatment I've been having, this seems to have
been reduced quite a bit, my eyes are far more convergent than they
used to be, and my binocularity seems much improved.

So, to describe what I see compared to a normal sighted person has to
take into account several factors, including how tired my eyes are,
or how stressed I am (stress affects nystagmus a lot). I do not see
the world moving from side to side because of my congenital nystamus
as my brain edits it out, nor do I see the world as a blur (like in
your image), I see a clear picture, but like you, when you look at a
very distant object, you can see it ok and it isn't blurred, you just
can't make out fine detail.



--
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biscuit
medicine forum Guru Wannabe


Joined: 24 Apr 2005
Posts: 296

PostPosted: Sat Jul 08, 2006 7:43 am    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

<acemanvx@yahoo.com> wrote in message
news:1152319937.412885.241340@b28g2000cwb.googlegroups.com...
| Ah I see. I will do more research on that. Do you see the world
| pixelized with anisometropia blurring? Can you describe what you see
| exactly?

With albinism, there are several other factors that affect vision:-
Nystagmus, Astigmatism, Photophobia, Squint and Strabismus.

I'm told that when I squint, it adversely affects the vision centres of the
brain, so I've been working on reducing that.

Nystagmus.. causes a problem because the brain has to snapshot images
instead of getting constant updates, so for a moving target, I'd see less
detail than a normal sighted person because of what is probably like a
strobing effect, you see the movement, but your brain only gets images now
and then and so has to fill in the gaps with a best guess.

Astigmatism.. in my case, my last eye test gave me figures of
Right Eye : Sph +7 Cyl -4 Axis 15
Left Eye : Sph +6 Cyl -2 Axis 175
So, as you can see, I need quite a high corrective lens, so my eyes are
trying to compensate for the imprecise nature of the lenses.

Photophobia.. this causes me to squint, so I have to ensure I wear a brimmed
hat and dark glasses outside else I have to squint a lot.

Strabismus.. With the treatment I've been having, this seems to have been
reduced quite a bit, my eyes are far more convergent than they used to be,
and my binocularity seems much improved.

So, to describe what I see compared to a normal sighted person has to take
into account several factors, including how tired my eyes are, or how
stressed I am (stress affects nystagmus a lot). I do not see the world
moving from side to side because of my congenital nystamus as my brain edits
it out, nor do I see the world as a blur (like in your image), I see a clear
picture, but like you, when you look at a very distant object, you can see
it ok and it isn't blurred, you just can't make out fine detail.
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acemanvx@yahoo.com
medicine forum Guru


Joined: 15 Nov 2005
Posts: 732

PostPosted: Sat Jul 08, 2006 12:52 am    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

Ah I see. I will do more research on that. Do you see the world
pixelized with anisometropia blurring? Can you describe what you see
exactly?
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biscuit
medicine forum Guru Wannabe


Joined: 24 Apr 2005
Posts: 296

PostPosted: Fri Jul 07, 2006 8:24 pm    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

<acemanvx@yahoo.com> wrote in message
news:1152299269.455500.108140@s53g2000cws.googlegroups.com...
|
| Adrian Parker wrote:
| > Hi,
| >
| > I've been told that in the eye of a person with albinism, there are
fewer
| > rods to 'see' fine detail of an image. So even if all the other eye
| > conditions were corrected, there would still be a problem seeing.
| >
| > Does anyone know what % the reduction of Rods is as compared to a normal
eye
| > ?
| >
| > --
| > Adrian Parker
|
|
| I read that albinos have less rods/cones so they are often legally
| blind. I read the posts of one in another forum who sees 20/150 and he
| considers himself lucky because some see much worse. Another described
| her vision as pixalized with antialising as the best description she
| could give. A normal person could look at an "E" and see it perfectly
| sharp. She would also see it sharp but it may be too small.
|
| http://www.yorku.ca/eye/popepix.gif
|
| This is the best description I can find. Again, albinos would NOT see
| blurry, but more like pixelized but not this exaggerated, just lacking
| any fine details due to low density of rods/cones.

Sorry, should have explained, I have albinism, so I know what the vision is
like, I am trying to find out about the general reduction of fine detail
receptor cells (rods) in the eye. I've been having neurofeedback to
correct the nystagmus and it has helped for near sight, but not long
distance, and I'm wondering if it is because of the fine receptors not being
able to resolve down to a small enough resolution.

My vision is betwen 6/24 and 6/36 (20/80 and 20/120)
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acemanvx@yahoo.com
medicine forum Guru


Joined: 15 Nov 2005
Posts: 732

PostPosted: Fri Jul 07, 2006 7:07 pm    Post subject: Re: Albinism and reduction of high definition receptiors Reply with quote

Adrian Parker wrote:
Quote:
Hi,

I've been told that in the eye of a person with albinism, there are fewer
rods to 'see' fine detail of an image. So even if all the other eye
conditions were corrected, there would still be a problem seeing.

Does anyone know what % the reduction of Rods is as compared to a normal eye
?

--
Adrian Parker


I read that albinos have less rods/cones so they are often legally
blind. I read the posts of one in another forum who sees 20/150 and he
considers himself lucky because some see much worse. Another described
her vision as pixalized with antialising as the best description she
could give. A normal person could look at an "E" and see it perfectly
sharp. She would also see it sharp but it may be too small.


http://www.yorku.ca/eye/popepix.gif

This is the best description I can find. Again, albinos would NOT see
blurry, but more like pixelized but not this exaggerated, just lacking
any fine details due to low density of rods/cones.
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biscuit
medicine forum Guru Wannabe


Joined: 24 Apr 2005
Posts: 296

PostPosted: Fri Jul 07, 2006 5:31 pm    Post subject: Albinism and reduction of high definition receptiors Reply with quote

Hi,

I've been told that in the eye of a person with albinism, there are fewer
rods to 'see' fine detail of an image. So even if all the other eye
conditions were corrected, there would still be a problem seeing.

Does anyone know what % the reduction of Rods is as compared to a normal eye
?

--
Adrian Parker
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