Author Topic: Is Presbyopia Real ? How to Avoid / Fix it ?  (Read 9947 times)

Offline Hillyman

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #15 on: October 31, 2013, 06:11:42 AM »
Whew.  I thought this thread was about presbyopia!

Offline Hillyman

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #16 on: October 31, 2013, 04:47:38 PM »
Seriously, Otis, *YOU* know what presbyopia is. http://en.wikipedia.org/wiki/Presbyopia


Offline OtisBrown

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #17 on: November 02, 2013, 07:39:25 AM »
Hi Steve,

The answer is indeed "Yes" - if he has the interest in doing so.

Otis


So it's yes.

Offline OtisBrown

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #18 on: November 02, 2013, 07:42:46 AM »
Hi Steve,

When I say yes, that you can get the eye to change its refractive state, from "plus" to "minus" (and stop at zero if you wish), then I must present the proven facts about this issue.  Here is what always happens:

http://www.ocf.berkeley.edu/~wildsoet/images/neg_lens_induce_myopia.swf

If you wish, you could maintain your refraction at 0.0 diopters (perfect - emmetropia - for life).

It just takes scientific knowledge and wisdom to do  it.

Otis
« Last Edit: November 02, 2013, 03:43:32 PM by OtisBrown »

Offline Hillyman

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #19 on: November 03, 2013, 09:45:51 PM »
The rationale behind Gottlieb's method is actually quite intelligible. It's the idea that the amount of accommodation can be increased by increasing convergence. When someone fails to accommodate, he can force accommodation to happen by crossing his eyes.

How come? The 3-cup exercise and its variants basically instructing people to focus on an object by focusing somewhere closer to the nose (I didn't know this when I did 3-cup). As a result, the visual axes needs to bend inward so that this can happen, which necessitate a fair amount of convergence. I found here an animation under this link illustrates this idea (notice how the visual axes intersect at a point that closer to the person):

http://www.forbestvision.com/dynamic-eye-exercises-for-better-vision/

Tom,

Thanks for the reply and the information.

When I do the 3 cups exercise, which for all intents and purposes is similar to the Gottlieb exercise, I can get a reverse effect: if I put one hand over one eye and then my cross my eyes in the 3 cups/Gottlieb way, the effort in crossing my eyes results in my active eye being able to see farther (!), i.e., something slightly blurred past my blur point comes into clear focus. The improvement is slight, no more than probably 0.25 diopter, but discernible and also repeatable. Of course, when I bring my hand down from the other eye, I find my eyes are crossed and I have a double vision. But it's curious that this effort of convergence gives me a reduced myopia, versus what would be the expected result of a reduced presbyopia (hyperopia). I can't figure this out!

Offline Hillyman

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #20 on: November 04, 2013, 06:04:14 PM »
Sorry, just to explain a little bit more on what I am doing with looking out of one eye and crossing the other eye: I put one hand over one eye to cover it, and then with the other eye open and still looking straight at the object, I cross the eye behind the hand. So the eye behind the hand (and being blocked from seeing) is at double the angle for such crossed-eye convergence. This is how I get that discernible improvement in acuity in the open eye as long as I do it.

If I changed sides and do the same with the other eye, the acuity improvement works on the other eye, too.

Offline Tom

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #21 on: April 06, 2014, 11:04:44 AM »
Hillyman, I have an explanation to your improved visual acuity during convergence - It might not convergence per se, but rather that moving ocular globe nasalwards puts the cornea in contact with eye socket, temporarily reducing corneal curvature. The fact that the improved acuity is temporary is consistent with inelasticity of ocular globe.

You are clearly getting somewhere with active focus. Thanks for sharing your recent experience with accommodation amplitude. All the more reasons to believe theorizing about the etiology of presbyopia can be useful.

(looks like tackling myopia, by learning a bit about all ocular issues, proved to be unexpectedly beneficial)

If presbyopia were indeed characterized by the stiffening of intraocular lens, then any effort in altering the shape of intraocular lens would help decrease its hardening rate. The ciliary and the intraocular lens are after all two different entities. Since the lens is not perfectly elastic, there is going to be a temporal delay between ciliary-choroidal response and lens thickening/thinning. In addition, the lens shape can be altered by both positive and negative accommodation, provided that you give enough time for the accommodative changes to sink in. If this is true, the rammifications lead to one passive method to delay presbyopia:

  • One way to prevent lens hardening, is by alternating between works involving moderate accommodation demand (e.g., reading), and works of moderate negative accommodation accommodation demand (e.g., distance gazing)

  • However, since any movement in crystalline lens would have helped delay lens sclerosis, a more sensible way would be to engage in intermittent distance gazing. This explains why sports like tennis work so well in keeping the lens mobile.

  • Saying that age alone determines one's accommodation amplitude is just plain false. For one, there is the fallacy of (linear) extrapolation. If the minimum amplitude were indeed 15- age/4 , then by the age of 60 you should get...hm..0D of amplitude.....by the time you reach the age of 80 you would have -5D of amplitude! Furthermore, the fact that behavioral parameters are not even acknowledged at all suggests how medieval the mainstream still are, in 21st century! (unfairly imposing my own standard to other professionals?) 8)

  • This explains how someone can be hyperopic or myopic, and still has reduced accommodation amplitude, as it is the alteration of intraocular lens shape that delay presbyopia, not the intensity of accommodation (positive or negative alike). You can have an hyperope with high accommodation lead, who never bother with any kind of close work (and uses plus lens temporarily to see small letters), or you can have a myope with high accommodation lag, wearing full minus prescription, who do intense close work but no substantial work involving changing focal planes. Both of them could very well experience reduced accommodation amplitude, in the long run.

  • Due to the temporal delay of lens thickening/shortening, quickly oscillating between two distances is not enough. Any accommodation-demanding work (positive or negative) requires some time for the effect to transfer to the lens.

  • One way to confirm this thesis is to compare people with professions requiring constant change of focal plane (e.g., athelete, archer, hunter-gatherer), with those who are not (e.g., office worker). It is counter-intuitive that the eyes are made to fail, at the speed that we currently witness.

Thanks to additional data, more details are coming out about an active method of presbyopia, which I call Focusing-Stress Reintroduction :) :

  • A slightly different perspective, is that modern medicine and visual habits accelerates presbyopia, by creating an environment where the eyes are not used the way they are intended for. In the natural environment, before widespread use of ophthalmic lenses, one would invariably find blurry objects around them, which requires them to actively work on focus. There is nothing wrong of that: focusing is there to be used and that's the way it should be. Dr. Antonia Orfield elaborates:

    Quote
    Full minus also takes away an individual’s ability to refocus at distance so that far vision does, indeed, become the passive process we have believed it to be.

  • Notice that without lenses, seeing blurry objects at far requires voluntary focusing, and the same applies to seeing blurry objects at near. Once lenses are accessible to the public, focusing becomes a vestigial mechanism. Putting on the glasses of right prescription creates immediate clarity, and by doing so, health is sacrificed in the virtue of comfort - The focusing mechanism now starts to atrophy really fast.

  • It means that we have to change our attitude about lenses, and our visual habits, by reintroducing the focusing stress that we have long lost and taken for granted. This is done essentially by embracing the blur and consequently adjusting oneself to them. Some examples of focusing-stress reintroduction includes:

    • Myopes deliberately using more positive lenses to induce blur. and hyperopes deliberately using more negative lenses to induce blur
    • Myopes avoiding leaning forward to see clearly, and hyperopes avoidng leaning backwards to see clearly. Blur clearing should be done sustainably, using methods such as eye rinsing, avoiding inflammatory/high-glycemic load diet (which could interfere with accommodation system), opting for higher-index ophthalmic/contact lenses and behavioural blur clearing techniques.

All right. Here's a nice quote from Dr. Alex:

Quote
A strong side benefit is that the healthier vision habits help protect and extend your accommodation range, so that you won’t later in life be stuck with needing a reading prescription along with the high myopia prescription. 
« Last Edit: August 17, 2015, 09:20:54 PM by Tom »
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Offline Alex_Myopic

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Re: Is Presbyopia Real ? How to Avoid / Fix it ?
« Reply #22 on: April 29, 2014, 08:33:32 AM »
The question is does someone use minus lenses to make their eyes go from plus, closer to 0 ?

In David De Angelis' book it analyzes how to use minus if you are over +3/4 hyperopic. Just like plus lenses but the direction of the book/monitor etc should be even closer until stronger minus.