Micropsia

[Han Sibot]

One symptom of the central serous retinopathy in my right eye is micropsia:
the characters that I focus on appear smaller than characters elsewhere on a
printed page. The apparent point size is reduced with about 7%. I thought
that micropsia results from ordinary optics, because the serous detachment
brings the retina closer to the lens. However, that idea requires a
detachment height of 1.4 mm (7% closer to the lens). That's unlikely for a
detachment with a diameter of about 0.6 mm. Is there another explanation?

[Evaristo]

On Wed, 19 Mar 2003 08:19:49 +0100, "Han Sibot" <han...@freemail.nl>
wrote:

Yes, it is a mental illusion.

Just like multiple images and other things.

--
"[the facts] may, and indeed must, win in the long run; but in the
meantime the world gropes needlessly in darkness and endures
much suffering that might have been avoided."

[Han Sibot]

Can't argue with that. You're the expert in mental illusions :-)

"Evaristo" <evar...@recalcati.it> wrote in message
news:8qpg7voi5ofg47hgn...@4ax.com...

[Han Sibot]

Another idea within optics may be stretching of the retina. If the
detachment forms a spherical surface, the stretching of the surface can be
calculated for given detachment heights. The diameter of the detachment is
0.6 mm. A detachment height of 0.1 mm results in 7% of stretch, and
consequently in 7% reduced apparent size of the image. Now, that's a
reasonable detachment height.

"Evaristo" <evar...@recalcati.it> wrote

[Evaristo]

On Wed, 19 Mar 2003 19:33:20 +0100, "Han Sibot" <han...@freemail.nl>
wrote:

>Can't argue with that. You're the expert in mental illusions :-)

Sure.
There are also mental illusions of perfect sight.
For example, ask someone who has normal or more than normal
sight to look at a distant small letter O.
Ask him if he sees the white center whiter than the white around
the letter. The white inside looks whiter while it is not.

Probably you and your friends will search into the chemicals of
retina cells for explanations, maybe you'll try to "cure" this
"defect" with glasses or laser.

Duh.

>
>"Evaristo" <evar...@recalcati.it> wrote in message
>news:8qpg7voi5ofg47hgn...@4ax.com...
>>
>> Yes, it is a mental illusion.
>> Just like multiple images and other things.
>

--

[Han Sibot]

For some time I have been wondering why I do not perceive a focussing
difference between the detachment zone and its surroundings. Such a
difference should exist because the detachment is closer to the lens.
However, the detachment height of 0.1 mm is equivalent to a rather small
refractive difference of 0.25 diopter. That seems to explain it.

"Han Sibot" <han...@freemail.nl> wrote

[Rishi Giovanni Gatti]

Han Sibot wrote:
> Another idea within optics may be stretching of the retina. If the
> detachment forms a spherical surface, the stretching of the surface can be
> calculated for given detachment heights. The diameter of the detachment is
> 0.6 mm. A detachment height of 0.1 mm results in 7% of stretch, and
> consequently in 7% reduced apparent size of the image. Now, that's a
> reasonable detachment height.

Your scientific expalantions fall short: can you tell me WHY all this
things should happen?

[Han Sibot]

"Rishi Giovanni Gatti" <g.g...@agora.it> wrote

> Your scientific expalantions fall short: can you tell me WHY all this
> things should happen?

Even Alice knew why all these things should happen:
"The time has come," the Walrus said,
"To talk of many things:
Of shoes--and ships--and sealing-wax--
Of cabbages--and kings--
And why the sea is boiling hot--
And whether pigs have wings."

[Rishi Giovanni Gatti]

It's interesting to see that you are flying so high in the Sky with
alice in Wonderland!!!

Finally, you have found your perfect match!