Re: Height of glasses lenses affects head position

William Stacy wrote:
> dumbstruck wrote:
> let's talk about practical life. If that patch of
> > fuzz in your periphery is a vehicle you need to know it's speed and
> > direction.
>
> You can't tell any more about its speed and direction if it's in focus
> rather than out of focus when relying on your peripheral vision. There
> is no difference.

I'm not talking about LEAVING it in peripheral; naturally you turn
almost 45 degrees to either see your potential assassin thru your wide
frames, or just a patch of ambigous fuzz just outside your narrow
frames. It's not a theoretical debate but something I live every other
day or so, when circumstances lead me to switch to narrow frames to
walk thru some crosswalks. It is undoubtedly a magnitude or so more
dangerous, with you having to scan 180 degrees at once to see if
drivers will run the walk light or are just playing chicken. With
narrow frames you can no longer keep all in sharp view in split
seconds required. Maybe the 180 case is less critical for drivers.

> It is NOT the "problem" of a small frame. As I pointed out in my other
> post, larger frames just move the blind area caused by lens edge and
> frame eyewire farther back and make it LARGER, thus obscuring a larger
> object. But then if you really believe you'll see better with a larger
> frame, they are still widely available, up to huge sizes.

Not concerned with that blindspot which is small enough (with thin
lenses and frame) to be erased by slight movements of the head or
scene. I don't see hardly any wide frames avail where I shop, except
for freak versions with enormous height. While these may be avail in
some areas, many may be restricted to a little HMO shop for instance.

> > P.S. Another hidden source of maiming and death that is needless result
> > of style probably has no remedy for the vision customer. The rearview
> > mirrors of cars are becoming no longer adjustable for their location,
> > just their tilt. For a tall driver this is directly in the way, and
> > you may as well paint the central quarter of the windshield black from
> > top to bottom!
>
> You could remove it completely and rely totally on your side mirrors,
> like all the truckers have to do, or replace it with a smaller mirror

Not on rentals or shared cars. Side mirrors have bad blind spots which
is why truckers tend to have them stuck way out. Mirror look hard to
substitute, but maybe I have to look more into this. What a tall
person actually has to do is rotate the mirror clockwise about 30
degrees or whatever it takes to lift the close edge up out of view
(except when the road dips).

> placed wherever you like. But then you are exaggerating the size of the
> mirror. It's really less than 5% of the area of the windshield, not 25%.

The mirror can be almost a foot wide; that would make your windshield
20 feet wide! Oh, you didn't accept the notion that it effectively
blocks 100% top to bottom. And the mirror is turned to you; look at
the angular percentage from left windshield edge to about an equal
angle to the right, where almost all action happens - that would be
more than a quarter obscured.

I'm not making this up - it just takes moments to have a near accident
in these cases where you don't take action on the mirror. You can't
see folks pulling in front of you from the right hand side, or even
cars ahead either coming or going, given wanders and dips in the road.
I hope folks will listen to what I'm trying to say rather than picking
literal nits since I don't have time to bulletproof these posts for
every possible shade of interpretation.

.

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