Mike Tyner wrote:
> "Simon Dean" <(E-Mail Removed)> wrote
>
>> Obviously the question is, how can you make sure you're slightly
>> undercorrected to avoid this "artificial contrast" of which he describes?
>
> The symptoms and the management are different for specific refractions (and
> ages). In any case, if he was discussing it, he was probably checking for
> it.
>
> "Too bright" and "contrast" usually mean you're accommodating more than
> necessary, or more than you're used to. It isn't always a problem. When it
> exceeds capacity, you get tired, blurry, or double, or achey.
So just to fill you in, to avoid any ambiguity... three years ago ish, I
went to my optician and had my usual excellent eye exam, with marginal
long sightedness and marginal astigmatism:
Right +0.50 Sph, -0.75 Cyl, 135 Axis
Left +0.75 Sph, -0.50 Cyl, 35 Axis
I suffer constantly from the tired, blurry, achey eyes that you speak
of, so thought it might be a great idea to see about getting some
glasses made up to see what things would be like.
Sure enough, things were incredible. Text was sharp, crystal clear, I
felt like I had less eye strain and things were great. Grey text was
black everything wonderful. But distance vision in those glasses was non
existant.
So, as you know, six months, to a year after having these glasses, I
started experiencing my odd effects of text jumping off a page at me,
disorientated reading etc and that's when I went to the eye clinic and
had all the electrical tests and MRI's done for the doc just to tell me
he can't find anything wrong but suggested a light sensitivity and
recommended comfort 41 lenses (that I gather, is a rather old idea and
is perhaps surpassed by the rather expensive Meares Irlen approach?).
Constantly over the past four years or so, I'd also say I believe that I
have various contrast issues. Various objects around me appear dull and
lifeless and a pair of sunglasses really make things come alive.
So my recent eye test, all I have now is very slight astigmatism again.
The optician only ran the standard tests, but we did talk about eye
strain, and I discussed about why a pair of glasses to counter those
previous "mild" results from a few years back, would give such amazing
results.
And he was almost suggesting that far from returning my vision to
"normal", that they'd be creating an almost artificial contrast and
thereby stressing my eyes out more than needs to be and therefore
possibly creating those odd vision issues I experienced. He was almost
suggesting a bit of blurriness is normal, and pristine sharp vision isn't.
>
> I avoid it by assuring that one step more plus, or less minus, creates blur
> at 20 feet. That should be enough, except that the answers can be different
> in dim vs bright, one eye vs two, farsighted or nearsighted, morning or
> evening, tense vs relaxed, young vs old, or one doc vs another.
This is where I get confused. You seem to be suggesting that adding a
little but more plus (in my case) will reduce eye strain, though my
optician was suggesting that the contrast generated by too much can
cause problems.
>
> The best test, once you have the glasses on, is a +0.25 hand-held lens. If
> it doesn't make roadsigns blurry, then something is off. But be sure it's
> "off" under all conditions, and be sure there are symptoms before asking for
> remakes.
>
> Most young people reflexively accommodate a little more than required, and
> all semivoluntary autonomic reflexes vary by nature. What's precisely
> "right" in your glasses is based on subjective comfort, catering to your
> reflexes, rather than conforming to a static anatomical snapshot. With
> presbyopia, most of the variability disappears.
>
That's over the top of my head :-)
Cya
Simon
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