Cataract Question

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Cataract Question

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Richard Jernigan

Posts: 3431
Joined: Jan. 20 2004
From: Austin, Texas USA

Cataract Question

This is a reply to a question from Ruphus on the General forum.

After replacing the lenses, two defects remain.

One is astigmatism induced by assymetry of the corneas that apparently increases with age. Ordinary optometry only makes a stab at correcting astigmatism, adding a single cylindrical component to the optical prescription, while the assymetry of the cornea is likely to be far more complex. Of course the replacement lenses contain no astigmatism correction, since their eventual orientation cannot be tightly controlled. So astigmatism correction is left to eyeglasses

The second defect in my case is a slight deformation of the retina near the fovea in the left eye. This arose when the vitreous humor, the gelatinous filling of the eyeball contracted and separated from the retina. This separation happens to everybody with age, though both I and my brother the M.D. were unaware of this.

Both conditions could be corrected with further surgery. Laser keratotomy could be used on the corneas. I was unaware that the slight retinal deformation could be surgically corrected, but it seemls pretty invasive.

The total effect of the remaining defects is quite small. The only real difference between my present vision, and the slightly sharper than average vision of my fifties is that then I could read a normal USA highway sign at a quarter of a mile, and now it's more like 150-200 meters. Further surgery didn't seem worth the risk.

RNJ

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 15 2013 16:37:12

El Kiko

Posts: 2697
Joined: Jun. 7 2010
From: The South Ireland

RE: Cataract Question (in reply to Richard Jernigan)

i got mine done years ago and have no problems at all ...
one of mine came from Fort Worth , Texas , and the other one , later, came from Oregon ..I think ....

I often wondered if that would qualify me for a green card as part of me does come from the states .....speaking as a cyborg that is.........

My vision is pretty good ..i always had a weak eye (left ) anyway ....and use reading glasses for close up stuff .......

I do remember a bit of laser tuning a few weeks after the op ...

_____________________________

Don't trust Atoms.....they make up everything.

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 15 2013 16:59:18

Ruphus

Posts: 3782
Joined: Nov. 18 2010

RE: Cataract Question (in reply to Richard Jernigan)

Thank you for the info!

Ruphus

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 15 2013 18:06:33

guitarbuddha

Posts: 2970
Joined: Jan. 4 2007

RE: Cataract Question (in reply to Richard Jernigan)

quote:

ORIGINAL: Richard Jernigan

. Ordinary optometry only makes a stab at correcting astigmatism, adding a single cylindrical component to the optical prescription, while the assymetry of the cornea is likely to be far more complex.

So astigmatism correction is left to eyeglasses

RNJ

Would I be wrong in assuming that a great deal of the heavy lifting with regard to correcting the effects of astigmatism is actually carried out by the visual cortex ?

I would assume so since throughout history most astigmatism has been asymmetrical and a stereoscopic image has been reported in all but the most extreme cases.

I seem to remember that an attempt was made to correct a flaw in the Hubble telescope principally through optical means.

Do you think Richard that sufficient attempts were made to simulate the working of mammalian wetware with software in that instance ? Or were engineers possibly too focused on a physical solution ?

D.

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 15 2013 23:11:13

Richard Jernigan

Posts: 3431
Joined: Jan. 20 2004
From: Austin, Texas USA

RE: Cataract Question (in reply to guitarbuddha)

quote:

ORIGINAL: guitarbuddha

Would I be wrong in assuming that a great deal of the heavy lifting with regard to correcting the effects of astigmatism is actually carried out by the visual cortex ?

I would assume so since throughout history most astigmatism has been asymmetrical and a stereoscopic image has been reported in all but the most extreme cases.

I would say yes, but the details of how the brain does this are far from fully understood.

quote:

I seem to remember that an attempt was made to correct a flaw in the Hubble telescope principally through optical means.

Do you think Richard that sufficient attempts were made to simulate the working of mammalian wetware with software in that instance ? Or were engineers possibly too focused on a physical solution ?

D.

Once analyzed, the error was seen to be relatively simple. The edges of the parabolic mirror were ground too flat. This was caused by miscalibrating a measuring instrument, and the mistake was not detected until the telescope was in space, due to poorly designed and executed quality control in manufacturing. The engineering solution was perfectly straightforward: grind a lens to compensate for the sight error in the mirror, and insert the lens into the optical path of the telescope. The actual installation and precise alignment of the lens in the telescope while it was in space was a major feat of astronaut skill.

Since we don't know the precise details of how the brain processes images, trying to make a software solution would have been pretty much a shot in the dark.

RNJ

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 16 2013 3:28:08

guitarbuddha

Posts: 2970
Joined: Jan. 4 2007

RE: Cataract Question (in reply to Richard Jernigan)

quote:

ORIGINAL: Richard Jernigan

quote:

ORIGINAL: guitarbuddha

Would I be wrong in assuming that a great deal of the heavy lifting with regard to correcting the effects of astigmatism is actually carried out by the visual cortex ?

I would assume so since throughout history most astigmatism has been asymmetrical and a stereoscopic image has been reported in all but the most extreme cases.

I would say yes, .

RNJ

To which ?

Anyway I seem to remember that there has been quite a history of problems with optical hardware in space.

Perhaps that shot in the dark could be useful in the future. The history of science is full of them.

A child can reach out and catch a ball. We have mathematical models which can simulate the childs prediction. I think that these forms of simulation weren't conditional on completing a model of the relevant neural networks. It was however noted that the prediction could be made.

It always amazes me just how long it took for mathematicians to simulate other innate human abilities. Chance in particular offers some embarrassment to the discipline. And yet once mathematicians really got into their swing the embarrassment was to human nature.

D.

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 16 2013 9:48:48

Richard Jernigan

Posts: 3431
Joined: Jan. 20 2004
From: Austin, Texas USA

RE: Cataract Question (in reply to guitarbuddha)

quote:

ORIGINAL: guitarbuddha

Would I be wrong in assuming that a great deal of the heavy lifting with regard to correcting the effects of astigmatism is actually carried out by the visual cortex ?

I would assume so since throughout history most astigmatism has been asymmetrical and a stereoscopic image has been reported in all but the most extreme cases.

Sorry, my answers should have been "no" and "i agree."

The hardware solution was obvious, and almost guaranteed to work, provided the on-orbit installation could be done. Had it been my decision, I would have gone with the solution that was implemented.

There is a great deal of image processing software in use now. None of it that I know the details of is based on an attempt to model how the brain does it. All of it is mathematics.

Of course I'm not saying there should not be a lot of effort devoted to understanding how the brain works. It is potentially one of the most important scientific efforts, in my opinion. I would classify the results so far more as "pure science" rather than ready for engineering applications. But I think the engineering applications, and the medical ones, will inevitably follow.

RNJ

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 16 2013 13:08:51

guitarbuddha

Posts: 2970
Joined: Jan. 4 2007

RE: Cataract Question (in reply to Richard Jernigan)

Applying 'natural selection' to algorithms sounds like a fun project. And probably resembles the process which takes place in the initial stages of problem solving which every child undergoes when growing a brain with the correct architecture for seeing.

Sadly only the very young have this extreme neural plasticity which is why if a child cannot see in the first year of life no physical correction can coax the brain into true vision later.

I miss science a little sometimes.

D.

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 16 2013 15:26:28

Richard Jernigan

Posts: 3431
Joined: Jan. 20 2004
From: Austin, Texas USA

RE: Cataract Question (in reply to guitarbuddha)

How the brain does it: as I understand it, we learn to see in the first few months after we are born. This results in our remarkable subconscious image processing.

Using mathematics, as does the image processing software I am aware of, is also the work of the brain, done consciously. It took centuries to develop and refine the concepts of modern mathematics. There was quite a flowering of this effort in the 20th century. The teachability of many mathematical concepts indicates that these concepts are well suited to our aptitudes and abilities.

It will be interesting to learn in detail how the brain does it subconsciously, and to find out which would be more efficient if implemented in software and the available hardware, if in fact one process is more efficient. To me, our current hardware and our software languages reflect strongly our style of mathematical thinking. Perhaps understanding subconscious image processing will prompt the development of new types of hardware and software.

RNJ

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 19 2013 6:13:26

guitarbuddha

Posts: 2970
Joined: Jan. 4 2007

RE: Cataract Question (in reply to Richard Jernigan)

quote:

ORIGINAL: Richard Jernigan

Using mathematics, as does the image processing software I am aware of, is also the work of the brain, done consciously.

The teachability of many mathematical concepts indicates that these concepts are well suited to our aptitudes and abilities.

RNJ

I thought turing macnines were constructed on logical lines, are these strictly mathematical as you suggest ? Consider these 'I always lie' and 'All statements involving x are untrue'.

Also I thought the physical properties of PnP junctions had at least as much of an influnce on computer design as the human brain.

Might it not be the case that the teachability of mathematics demonstrates the capacity of the human brain for flexibility in its ability to instigate and mirror different modes of thought ? Famously empathy is a peculiarly human phenomenon. After all mathematics is not the only thing which can be taught. And in fact many things can be taught which are in fact morally and intellectually inferior and yet may be capitulated to even by an individual of 'high intelligence'.

This would suggest to me that the kind of mathematics which is being used for some human subconscious thinking is not necessarily that which is readily mirrored by our current computers nor a consequence of strictly logical problem solving. Hence my suggestion for an 'evolutionary' approach.

Consider these two statements and tell me which seems more accutrate.

'All we know of mathematics is a product of the human imagination'.
'All human thinking is a product of mathematics as we know it.'

Anyway just a thought.

D.

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 19 2013 9:22:29

Richard Jernigan

Posts: 3431
Joined: Jan. 20 2004
From: Austin, Texas USA

RE: Cataract Question (in reply to guitarbuddha)

Having been trained as a research mathematician, I include mathematical logic such as the Turing machine under "mathematics". The computer was developed to perform mathematical calculations--I include cryptology under "mathematics" as well. Turing and Von Neumann were concerned to see that the designs were as capable as possible, given the approach to mathematical logic that was most prevalent at the time.

Computers built first from discrete semiconductor components, then from increasingly integrated and miniaturized silicon chips, mimic almost exactly the design architecture of their vacuum tube predecessors.

RNJ

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 19 2013 18:54:29

Richard Jernigan

Posts: 3431
Joined: Jan. 20 2004
From: Austin, Texas USA

RE: Cataract Question (in reply to guitarbuddha)

quote:

ORIGINAL: guitarbuddha

This would suggest to me that the kind of mathematics which is being used for some human subconscious thinking is not necessarily that which is readily mirrored by our current computers nor a consequence of strictly logical problem solving. Hence my suggestion for an 'evolutionary' approach.

That was the thought I had in mind when contrasting the conscious and subconscious approaches, but which I failed to make clear.

Evolution has produced peacocks and flatworms, both of which prosper at present. I see no reason to think that the evolution of our usual algorithmic proceedings would lead to an emulation of our neural processing of images.

So-called "neural net" software might show greater promise, but we continue to learn more about how our own neurons work, so today's (or last month's?) neural net software needs to be updated to more closely approximate the operations of our nervous system.

quote:

Consider these two statements and tell me which seems more accutrate.

'All we know of mathematics is a product of the human imagination'.
'All human thinking is a product of mathematics as we know it.'

Anyway just a thought.

D.

Surely you don't suppose I place any credence whatsoever in the second one?

RNJ

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 19 2013 19:06:09

guitarbuddha

Posts: 2970
Joined: Jan. 4 2007

RE: Cataract Question (in reply to Richard Jernigan)

quote:

ORIGINAL: Richard Jernigan

Computers built first from discrete semiconductor components, then from increasingly integrated and miniaturized silicon chips, mimic almost exactly the design architecture of their vacuum tube predecessors.

RNJ

That's what I was thinking when I wrote this above.

'I thought the physical properties of PnP junctions had at least as much of an influnce on computer design as the human brain'

And similarly to the directionality that this has imposed on computer design I would imagine that the automated algorithms or programs and the orthodoxies for their design might have a similar inertia. One which may restrict their ability to simulate all of the processes which may be being carried out in human subconscious calculation.

And of course I didn't expect you to agree with the second statement but I have a thing about symmetry and it reflected it's partner grammatically and also the opening of my last post.

I am a silly man.

D.

REPORT THIS POST AS INAPPROPRIATE | Date Nov. 19 2013 22:46:39