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+--- Thread: Zenni optical (/showthread.php?tid=406)
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Re: Zenni optical - otis - 06-11-2007
Dear Otter,
Subject: Over-prescription -- yet again.
If you can read 20/80 (read or guess 1/2 the letters
correctly, then you are profoundly over-prescribed -- in my
opinion.
I know that Bates never covered this subject -- but
your over-prescription is the result of prescribing
to "best visual acuity".
The purpose of you reading your Snellen is to have
you OBJECTIVELY confirm this truth.
I would SUGGEST getting a -1.5 diopter minus from
Zennioptical. That will give you better-than
20/40, and perhaps 20/20 THROUGH that
-1.5 diopters lens.
Do no waste your money on the -2.75 diopter lens -- that
is STILL over-prescribed.
It I were reading confirmed 20/80, then that is what
I would do.
Others are welcome to comment on this issue.
Best,
Otis
Re: Zenni optical - Otter - 06-12-2007
i can't see 20/40 through -1.75 lenses. Dave once said that someone with 1.5 diopters can read 20/40 but someone else with 1.5 can read 20/80
Re: Zenni optical - otis - 06-12-2007
Dear Otter,
Subject: Nice thing to have.
The issue here is to personally determine what strength
minus is required to clear the REASONABLE 20/40 line.
In this case, having the correct "instrument" is critical,
namely a trial-lens kit.
With you at 20/80, you would then use
stronger minus until you cleared the 20/40 line -- UNDER
YOUR CONTROL.
That would give you the weakest lens possible, that
meets your requirement to have functional distant vision.
The trial-lens kit sells for about $190, and would
be of value for any Bates group.
Note, this is ONLY FOR MEASUREMENT, and
to have you confirm these issues youself.
Since you have determined that a -1.75 diopter will not
clear the 20/40 line, you should get a stronger
minus of perhaps -2.5 diopters -- as you previously
guessed.
This is still better than your original -3.75 diopter lens.
If you are effective with Bates, then you will
see your IVAC Snellen slowly clear (by your
judgment).
Best,
Otis
Re: Zenni optical - Otter - 06-12-2007
What is the axis for? I know it has something to do with astigmatism. will it make a difference if i ignore the 116 and 98 degrees axis in my eye if I'm to get reduced prescription?
Re: Zenni optical - otis - 06-13-2007
Dear Otter,
Subject: The angle of astigmatism.
Any suggestions or advice are the proceedure
I would want used on ME.
What you decide is up to you.
A value of less than 1 diopter (i personally
will ignore) -- provided the spherical
will give me 20/40 or better.
If you ignore the 1 diopter astigmatism,
the angle has no meaning.
I believe you said 1/4 diopter, which is
just barily measureable! The next
OD measurement could be zero astigmatism
for you.
Make you choice accordingly.
Otis
Re: Zenni optical - NoBones - 06-13-2007
I dont think I understand this. I know that people here have a goal to remove dependence on eyeglasses. Good goal. Bates, though, talked about a sort of mental strain as the cause of visual defects.
"Asthenopia" is what the doctros call eyestrain. According to studies like:
Click Here
some forms of astigmatism (what Otter may get if he doesn't wear his corrective lenses) CAUSE eyestrain.
How does one reconcile those two situations??
Re: Zenni optical - esthervdw - 06-13-2007
Hi NoBones
You wrote:
"some forms of astigmatism (what Otter may get if he doesn't wear his corrective lenses) CAUSE eyestrain."
I looked at the study you provided a link to, and it makes me wonder why you think this study proves that astigmatism causes eyestrain. If I read and understand it correctly, the people studied had good vision, they did not have astigmatism. They were asked to read under various conditions, one of which was 'mixed astigmatism'. As they did not have astigmatism themselves, this must have been created for them with lenses. After reading with these lenses they reported "internal strain" such as headaches. The report says this internal strain is caused by mixed astigmatism conditions, as opposed to "external strain" (such as dry eyes) which was caused by other conditions.
They basically conclude that there are 2 different types of symptoms resulting from eye strain, some internal, some external, and that mixed astigmatism conditions caused internal strain.
Like I said, the people studied did not have astigmatism, so it must have been created for them with lenses. Does this mean astigmatism caused the strain, or the lenses caused the strain?
Common sense says the lenses did.
Bates correctly noticed that strain is the cause of vision problems, including astigmatism. This is not a case of which comes first, the chicken or egg, the strain or the astigmatism. To me it is obvious that strain creates the initial astigmatism, and without strain, there is no astigmatism.
If lenses in front of healthy eyes mimic astigmatism, the healthy eye likely will start to strain, same as any type of lens causes eyestrain in healthy eyes. Just ask someone with good eyesight to try on a pair of myopic, astigmatic or hyperopic glasses from a friend, and watch their reaction as they try to see through these lenses.
Now regarding the rest of your statement: "astigmatism (what Otter may get if he doesn't wear his corrective lenses)"
According to Dr Bates, the only reason Otter would get astigmatism is when he strains his eyes. Compensating lenses do not help Otter to overcome whatever eyestrain or astigmatism he already has, and they certainly won't stop him from getting astigmatism if he has a habit of straining his eyes. Instead, they will reinforce any strained habits and can contribute to worsening vision.
Lenses are never corrective; they only compensate for a refractive error, they cannot correct it. What corrects the error is an awareness of strained vision habits and a subsequent return to natural vision habits. That's when vision truly clears up, and such natural clarity of vision can never be attained with lenses, no matter how 'good' they are.
I guess this is all just my opinion, but maybe it helps clear up this question for you.
Esther
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Re: Zenni optical - NoBones - 06-13-2007
esthervdw Wrote:Hi NoBones
You wrote:
"some forms of astigmatism (what Otter may get if he doesn't wear his corrective lenses) CAUSE eyestrain."
I looked at the study you provided a link to, and it makes me wonder why you think this study proves that astigmatism causes eyestrain. If I read and understand it correctly, the people studied had good vision, they did not have astigmatism. They were asked to read under various conditions, one of which was 'mixed astigmatism'. As they did not have astigmatism themselves, this must have been created for them with lenses. After reading with these lenses they reported "internal strain" such as headaches. The report says this internal strain is caused by mixed astigmatism conditions, as opposed to "external strain" (such as dry eyes) which was caused by other conditions.
They basically conclude that there are 2 different types of symptoms resulting from eye strain, some internal, some external, and that mixed astigmatism conditions caused internal strain.
Like I said, the people studied did not have astigmatism, so it must have been created for them with lenses. Does this mean astigmatism caused the strain, or the lenses caused the strain?
Common sense says the lenses did.
Meh. Do guns kill people or do bullets kill people? The lens introduced astigmatism. If the lens had been plano, do you think it would have induced asthenopia? I doubt it. It seems pretty fair to me to subject an otherwise healthy subject to various conditions and see how the body reacts. I think that's what this study showed: certain internal, and certain external factors caused ocular stress. Astigmatism was one external factor that causes eyestrain.
I don't necessarily believe that every single person with my prescription gets asthenopia if they don't wear their glasses, but surely some do. I think it's age, accommodative amplitudes, ciliary tonus, general health and well being, lighting, etc.
Quote:Bates correctly noticed that strain is the cause of vision problems, including astigmatism. This is not a case of which comes first, the chicken or egg, the strain or the astigmatism. To me it is obvious that strain creates the initial astigmatism, and without strain, there is no astigmatism.
I'm not sure that' correct. I dont mean any offense here. I just mean to say that which is cause and which is effect doesn't seem so clear to me.
Quote:If lenses in front of healthy eyes mimic astigmatism, the healthy eye likely will start to strain, same as any type of lens causes eyestrain in healthy eyes. Just ask someone with good eyesight to try on a pair of myopic, astigmatic or hyperopic glasses from a friend, and watch their reaction as they try to see through these lenses.
But I have healthy eyes except for about 1.5d of astigmatism in both, +/-. They're strained when I try to go without my glasses, but if I use the bag of corn thing and then put my glasses back on, I'm no longer straining to see. They strain when I leave them off.
Quote:Now regarding the rest of your statement: "astigmatism (what Otter may get if he doesn't wear his corrective lenses)"
According to Dr Bates, the only reason Otter would get astigmatism is when he strains his eyes. Compensating lenses do not help Otter to overcome whatever eyestrain or astigmatism he already has, and they certainly won't stop him from getting astigmatism if he has a habit of straining his eyes. Instead, they will reinforce any strained habits and can contribute to worsening vision.
That's directly the opposite of my experience, but it's jsut my experience.
Quote:Lenses are never corrective; they only compensate for a refractive error, they cannot correct it. What corrects the error is an awareness of strained vision habits and a subsequent return to natural vision habits. That's when vision truly clears up, and such natural clarity of vision can never be attained with lenses, no matter how 'good' they are.
I understand that this is the premise on which Bates theory is based, but my first-hand experience tells me that my particular breed of strain stays away with the glasses and comes back without them. That's why I'm curious about the approach, and the wisdom of that approach when somebody tries going without corrective lenses.
Quote:I guess this is all just my opinion, but maybe it helps clear up this question for you.
I appreciate your feedback. I think there are a lot of unknowns here, but I'm eager to learn.
Re: Zenni optical - Otter - 06-13-2007
You still havent answered my question otis. Should I ignore the 116 and 92 axis in my eyes if I'm to get reduced-prescription glasses?
Re: Zenni optical - esthervdw - 06-13-2007
Quote:Meh. Do guns kill people or do bullets kill people? The lens introduced astigmatism. If the lens had been plano, do you think it would have induced asthenopia? I doubt it. It seems pretty fair to me to subject an otherwise healthy subject to various conditions and see how the body reacts. I think that's what this study showed: certain internal, and certain external factors caused ocular stress. Astigmatism was one external factor that causes eyestrain.
The plano lens would likely not cause (much) strain, the astigmatic lens most certainly does. The point I wanted to make that perhaps didn't come across clear enough is that astigmatism was NOT a factor in this study, as the people studied had healthy eyes WITHOUT astigmatism. The factor that caused the strain was the astigmatic LENS. (just using caps to emphasize and hopefully clarify the difference)
Quote:I don't necessarily believe that every single person with my prescription gets asthenopia if they don't wear their glasses, but surely some do.
Yes, people who have blurry vision have a tendency to strain more when they don't wear compensating glasses.
Quote:But I have healthy eyes except for about 1.5d of astigmatism in both, +/-. They're strained when I try to go without my glasses, but if I use the bag of corn thing and then put my glasses back on, I'm no longer straining to see. They strain when I leave them off.
I understand what you're getting at. It probably seems like you don't strain when you wear glasses, because the strain that causes your astigmatism is chronic and as such it is no longer noticed by you. The additional strain when you don't wear glasses is something you do still notice. If you wish to overcome the strain, the idea is to first learn not to strain when you take your glasses off. That is what the Bates method is about: learning to use your eyes in a relaxed way, without glasses.
Glasses do not help you overcome the chronic strain; instead they reinforce it and are part of the reason that it has become a chronic strain. With a new awareness of how you use your eyes, and avoiding the strain by using the Bates method, you create an opportunity for the old strain to let go, and therefore for clear vision to return.
Hope that helps.
Enjoy your path to clarity.
Esther
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Re: Zenni optical - esthervdw - 06-13-2007
Hi Otter,
Quote:Should I ignore the 116 and 92 axis in my eyes if I'm to get reduced-prescription glasses?
Perhaps you misunderstood Otis, because he already wrote:
Quote:If you ignore the 1 diopter astigmatism, the angle has no meaning.
I'll explain it a bit more.
If I had an Rx with an astigmatism cylinder of 1 diopter, and I wanted to practice more relaxed vision habits with reduced prescriptions, I would leave out the astigmatism correction.
The astigmatism is written as a combination of a cylinder (-1.25 for example) at a certain axis (116 degrees for example). So if one leaves out the cylinder, the axis is no longer relevant. That means I could ignore those 116 and 92 axis numbers, as well as the cylinder, and get just the sphere of the Rx.
The reason for doing so would be to give my eyes a chance to get out of that astigmatism Rx. If the astigmatism Rx is in the glasses, the eyes have to keep that lopsided shape in order to see clearly through those glasses. Such glasses therefore keep the astigmatism going.
When a person uses reduced prescription glasses without astigmatism compensation, it is important to learn relaxed ways of seeing, else the strain that is already in the eyes will likely get worse and instead of progress to clear vision they may end up seeing worse.
Esther
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Re: Zenni optical - otis - 06-13-2007
Dear Otter,
With your previous prescription (from my memory):
Spherical, Astigmatism, Angle
-3.75 1/4 116
and
-3.75 1/4 93
IF IT WERE ME, I would ignore the astigmatism.
Otis
Otter> You still havent answered my question otis. Should I ignore the 116 and 92 axis in my eyes if I'm to get reduced-prescription glasses?
++++++++++
Yes, because if you remove the 1/4 diopter of astigmatism,
you have no "angle" to go with it.
If you wished to convert to spherical equivalent,
you would take 1/2 the astigmatism, and add
it to the spherical part, to calculate
the spherical equivalent.
Thus you would add 1/8 diopter
to the spherical part.
Hope this clarifies.
Otis
Re: Zenni optical - Otter - 06-13-2007
otis Wrote:Yes, because if you remove the 1/4 diopter of astigmatism,
you have no "angle" to go with it.
that answers my question. thx otis