How Much Can My Eyes Changes?

I've been wearing glasses for about 4 1/2 years now.

My first prescription, Jan '03, was
SPH CYL AXIS ADD
-.87 +.25 90 +1.25
-.87 +.25 90 +1.25

Then in Feb '04 it was
SPH CYL AXIS ADD
-.75 - - +1.75
-1.00 - - +1.75

Now, Aug '07, it is:
SPH CYL AXIS ADD
-.75 - - +2.25
-.75 - - +2.25

I got progressive lenses based on my August '07 prescription in early
September.


Furthermore I've noticed a couple of interesting phenomena.

1. I have a digital alarm clock on my dresser about 10 feet from where
I sleep. The numerals are about 3/4 of an inch high. When I look at
the clock a few minutes after retiring, with the lights off, the
numbers are not in focus. However when I wake up in the morning I can
read the clock perfectly. Crystal clear.

2. When I go grocery shopping I have noticed that sometimes I can read
far away category signs hanging above the aisles with ease and
sometimes they aren't in focus. I've compared this on several
differing occasions from the same spot in the store on the same far
away sign with varying results.

3. I've noticed that highway signs viewed from a certain distance that
used to be clear when I first got my new glasses are now not as clear.

I've taken my glasses to three different optometrist's shops and had
them check my glasses on a lensometer. They all come back with -.75 on
the OD measurements and (2 out of 3) with +2.25 on the add portion.

So what's going on? Have my eyes changed in 2 months? Do they change
from day-to-day? Overnight?

How do you explain no cyl. or axis components in my last 2
prescriptions?

 

So what's going on? Have my eyes changed in 2 months? Do they change
from day-to-day? Overnight?

Otis> None of the measurements are "perfectly accurate". Depending
on measurement conditions, you could see variations of 1/4 to
1/2 diopter -- depending on the OD making the measurements.


How do you explain no cyl. or axis components in my last 2
prescriptions?

Otis> Again, small variations. The smallest "prescription" value
is in 1/4 diopter increments. It could be that the OD simply
rounded "up" or rounded "down" -- depending on the
judgment of the OD -- of course.

Best,

Otis

 

Sorry. Rishi Giovanni Gatti (Zetsu), Lena102938, and Otis Brown are
trolls who haunt s.m.v.

Rishi has published, and is trying to sell worthless books.

Otis is pathologically dishonest and actually hurts people.
Following his advice can induce double vision in those
not working closely with an eye doctor.

Lena102938 uses anti-eye doctor rhetoric as a substitute for ANY
actual information. It seems she now has to wear glasses and has
developed a pathological (and ILLOGICAL) resentment toward the
industry that "foisted these glasses upon her."

You'd do well to ignore them and wait for responses from the
caring, compassionate eye doctors who DO also participate in this site.

 

A camera lens (like the eye) can only be in absolute focus at one distance
at any given time. You adjust the focus of a camera lens depending on how
far the object is from the film plane. In the human eye, we rely on the
muscles surrounding the eye to change the shape of the eye to adjust focus
between near and far.

However, as you get older, the muscles in your eye are weaker and less
flexible, and less able to make the necessary adjustment. That is also why
your close-up Rx (add power) increases as you age. Wearing glasses can
actually make the muscles even weaker because you are no longer using these
muscles as much to accommodate and they deteriorate somewhat from lack of
use.

By the same token, when you first waken in the morning, the muscles in your
eye are less tired than later in the day, and you may be able to accommodate
better.

Also, you may be squinting when looking at the clock in bed, which increases
the depth of focus of your eyes and compensates for the need to focus
up-closely, in the exact same way a camera has an increased depth of focus
when the lens aperture is made smaller (as the f-stop is larger).

 

The lens is part of the eye.

It is both. That is why a person's eyes can get "tired." A lens does not
loose flexibility in a single day.

Founded and factually correct. I am not suggesting (unlike some others on
this newsgroup) that one forgo wearing glasses if they are needed, but one's
uncorrected vision does get a little worse if the eye muscles are not used
as much.

 

i thought your explanation of his variations in vision were pretty
good but I disagree with the above statement. perhaps this might be
true for a hyperope who is early into presbyopia but in the vast
majority of cases the use of spectacle correction has no effect on
further weakening of the ciliary muscle.

 

Thank you. It was aimed for a consumer, not for someone who is in the
optical professions. Those in the optical professions will probably continue
to nitpick it, even if that does not help the patient better understand
their vision.

Since I am hyperope, I can say with personal experience that wearing glasses
can be slightly addictive in terms of loosing the ability to accommodate.
This is especially true for patients who are younger than the OP so perhaps
you are correct that it may not be a significant factor in this case. But I
suspect could be a slight factor.

However, by no means I am aligning myself with the quacks on this newsgroup
who advocate not wearing glasses for this reason. But I do believe that is
better to slightly under-prescribe than to slightly over-prescribe (which is
a common problem for hyperopes IMO).

 

The shape of the eye does affect how well the image is properly focused in
the eye. A hyperope (farsighted) person has an eyeball that is too short
(too round), and a myope (nearsighted) person has an eyeball which is too
long (not round enough). Both of these conditions cause the retina to be in
the wrong position relative to the lens. You can blame the shape of the lens
or you can blame the length of the eyeball (which determines how far away
the retina is from the lens) for the inability to see clearly in these
cases. In addition, many people have at least some astigmatism, which is
another deformity in the shape of the eye.

Obviously, the ability to focus the lens on the retina for both objects
close by and objects at a distance also depends on other factors besides the
initial shape of the eye, and the ability to see at both distances clearly
will change as one gets older (even a person with 20-20 vision when younger
will likely need reading glasses when they get older). But the initial shape
of the eye is one of the factors.

I certainly do not advocate curing any vision problem by forgoing glasses,
however, as I stated, it is better for a younger person (IMO) to be slightly
under-corrected in many cases.

 

you are the type of patient I referred to as the possible exception.
hyperopes who are approaching middle-age have reduced ciliary muscle
capacity. Plus lenses, which sometimes cause visual complaints in
younger patients particularly at distance, all of a sudden can become
"appreciated." if that's you, then all I can say is-- it will get
worse. its not the glasses doing it-- its your eyes aging.

 

just from personal experience I kinda went through the same thing. I
had PRK on my -10 vision. I am back to wearing glasses/contacts. I had
my surgery last year and my vision has changed about 4 times over the
summer, but ever so slightly. I am somewhere around -0.75, -0.25.
That's better then it's been in my entire life and I am grateful for
that. I still have to go back...but I am waiting to see if my eyes get
worse. 3 % chance that can happen and I am just unlucky that way.
My mother on the other hand is 56 years old and her vision actually
got better! you would think with age it would worsen. So with the eyes
any change in vision is possible.

 

FROM: http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=915798

1. Apparatus has been designed to alter the shape of the human lens by
tensile forces applied to the zonular fibres indirectly through the
ciliary body. The changes in dioptric power of the lens for
monochromatic sodium light were measured at the same time.
Simultaneous serial photography, and direct measurement enabled one to
relate a change in shape of the lens to the change in dioptric power.
Subsequently, the same lens was isolated and spun around its antero-
posterior polar axis and high speed photography recorded its changing
profile.

2. By comparing the changes in lens profile due to zonular tension and
centrifugal force respectively, the force developed in the zonule for
a given change in the shape of the lens could be calculated. Changes
in dioptric power associated with those of shape can thus be related
directly to the force of contraction of the ciliary muscle necessary
to reduce the initial tension of the zonule in the unaccommodated
state.

3. The force of contraction of the ciliary muscle as measured by
radial force exerted through the zonule and the change in dioptric
power of the lens were not linearly related. The relationship is more
exactly expressed by the equation [Formula: see text] where D =
amplitude of accommodation in dioptres (m-1), FCB = force of
contraction of the ciliary muscle as measured by changes in tension of
the zonule (N), Kdf = dioptric force coefficient and is constant for a
given age (m-1N-½ × 102·5). This coefficient is 0·41 at 15 yr and 0·07
at 45 yr of age.

4. In youth for maximum accommodation (10-12 D) the force is
approximately 1·0 × 10-2 N while to produce sufficient accommodation
for near vision (3·5 D) the force is less than 0·05 × 10-2 N.

5. After the age of 30 yr the force of contraction of the ciliary
muscle necessary to produce maximum accommodation rises steadily to
about 50 yr of age and thereafter probably falls slightly. At about 50
yr of age the ciliary muscle is some 50% more powerful than in youth.

6. Even if hypertrophy of the muscle did not occur the amplitude of
accommodation would be reduced at the most by only 0·8 D of that
observed at the onset of presbyopia

 

So with the eyes any change in vision is possible.

Yes all functional and organic troubles of the eye are not only
changeable, but also curable in their entirety. It is only required
that a person practices intelligently the methods of rest and
demonstrates that his sight can spontaneously return when he sees
without effort or strain.

 

Sorry. Rishi Giovanni Gatti (Zetsu), Lena102938, and Otis Brown are
trolls who haunt s.m.v.

Rishi has published, and is trying to sell worthless books.

Otis is pathologically dishonest and actually hurts people.
Following his advice can induce double vision in those
not working closely with an eye doctor.

Lena102938 uses anti-eye doctor rhetoric as a substitute for ANY
actual information. It seems she now has to wear glasses and has
developed a pathological (and ILLOGICAL) resentment toward the
industry that "foisted these glasses upon her."

You'd do well to ignore them and wait for responses from the
caring, compassionate eye doctors who DO also participate in this
site.

 

I started wearing glasses/contacts about 15 years ago. The first few
years that I went, each time I needed a stronger presciption. Then I
went several years where my eyes stayed the same. The last three
years that I have gone to the eye doctor, my eyes have gotten better
and my presciption has been decreased. Is this a natural process with
peoples eyes?

 

Nice group you got here. Not many answers to be found. Thanks to Otis
and Mark A for at least taking a shot at it.

No one attempted to answer Katz24's either. Just a lot of bickering
and one-upmanship.

SO...


Have my eyes changed in 2 months?
Do they change from day-to-day?
Overnight?

And no, Mark, I'm not squinting when I wake up in the morning and can
see the numerals on my digital clock with clarity.

 

Mark A did fine.

In the case of Otis, you're in trouble if you think that WRONG answers
are better than NO answers when it comes to vision and health.

Good luck!

 

I have not mixed up anything. You are the one who is seriously confused.

Hyperopes (too short) and myopoes (too long) have mis-shaped eyeballs,
despite your pathetic attempts to draw attention away from your prior
misstatements,

 

You also seem to have a severe case of attention deficit disorder since you
have posted the same thing 3 times. I would suggest you seek medical
attention for your condition.

 

Your eyes can change from hour to hour depending on how tired they are and
your general health. A .25 diopter change is not significant and there might
be that much variation in eye exams even if given by the same person back to
back, not to mention if they are given by different providers.

The exact Rx can easily depend on the thoroughness of the optometrist or how
careful the patient is when answering (which is better, 1 or 2). In
addition, the Rx can depend on the philosophy of the provider in how much
correction you should be given based on their interpretation of your
specific needs (especially in the near vision area).

Furthermore, since you have progressives, even the slightest shift in how
the frame sits on your face can have a significant effect on your vision.
However, this can mitigated by getting a progressive using an advanced lens
design, a high quality material with high abbe value (not polycarb and not
super-high index), and a proper fitting by a trained professional.

Just asking.

 

hello,
the true cause of presbyopia is not known. the assumption that loss
of pliability of the lens is the cause was offered up by Helmholtz
over a century ago and has been accepted without much verification.
in contrast, an alternative theory, and what is currently my favorite,
is proposed by Schachar. he suggests that the constant growth of the
lens throughout a person's lifetime results in it's growth to a size
where the zonule fibers become slack and no longer can effectively
pull on the lens and change its shape. according to him the
pliability of the lens is not the cause, nor is muscle atrophy,
although atrophy occurs as a secondary effect (disuse atrophy). here
is a reference to his theory, which is the basis of an experimental
surgical technique using scleral expanding bands to reverse
presbyopia. for a brief time I worked at a center that was involved
in clinical trials for this method so I had an opportunity to
understand it's basis fairly well.

http://www.emedicine.com/oph/topic723.htm

so in a nutshell, the true cause of presbyopia is not known. for many
many years students and doctors have been presented with the Helmholtz
explanation as if its the gospel truth and if you search the
literature on the topic you will find declarative texts that simply
assume it. Not so butterfly!

anyway, it is definitely clear that ciliary muscle atrophy does indeed
occur at approximately the time that presbyopia manifests. that does
not necessarily mean that it is the cause of presbyopia-- if ciliary
muscle contraction occurs without generating tension on the zonule
fibers that connect it to the lens, such as would occur if the lens
has grown excessively large, then disuse atrophy would result.
regardless of the cause, the ability of the ciliary muscle to
compensate for hyperopia clearly is reduced as a person ages.