Dr. Judy, Mark A and Robert Martellaro and all

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Father Times - 04 Dec 2004 14:12 GMT

Good Day,

I have read the excellent replies from Dr. Judy, Mark A and Robert
Martellaro and read hundreds of posts to this group. I now feel like a
slightly knowledgeable consumer. Plus a lot of this is subjective unless
you can shop for six months to perfect the exact physics of your individual
needs.

My prescription started out as:
O.D. +0.50 -0.75 X 090
O.S. +0.50 -1.00 X 094
Add +1.50

I have since gone back and asked for two lined bifocals. One for driving
and one for computer work.
At this point I feel that I can not live without good intermediate vision
for computer screens, wide mechanical drawings and looking into controller
panels hanging on a wall in a plant.

Likewise, I feel that I need a wide field of view for driving, going to the
movies and my 100 mile bike rides.
From what I gather, progressive lenses either give you a wide field of view
for distance or intermediate vision but not both.

My doctors changed my prescription to . . .
Driving
Sphere Cyl Axis
+.5 -.75 90
+.5 -.1. 94
Add .75 The optician made the seg hght 17 (35 mm width)
Computer
Sphere Cyl Axis
+1 -.75 90
+1 -.1. 94
Add .75
Add .75 The optician made the seg hght 18 (35 mm width)

Do these prescriptions make sense when compared to his original
prescription?

They are both CR39 $40
with Vivx AR $30
Nathan Flex Titanium $100.
The frames were the only ones that had the height the optician recommended
and provided a quasi text book fit. Her assistant weeks earlier had said
that any height would do for progressives. They will be in two weeks.

Between the two bifocals, I believe that I have four different focal
distances (two different intermediate distances). Is this correct?

I shopped Wal-Mart, Sam's, BJ's and Costco. My particular Sam's was not
very knowledgeable. Wal-Mart had both good and bad. BJ's was very honest.
Costco won out because they had CR39 and supposedly a durable AR and the
lead optician was recommended.

I may still pursue Varilux, Solamax, ,Rodenstock and Essilor Natural (are
these Ovation?). I will probably then work with an independent optician to
avoid polycarbonate and to really know what I am buying.
My next effort will be for my wife and daughter's glasses.

Thanks for the wonderful information and I look forward to your additional
comments.

Father Times

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Father Times - 04 Dec 2004 15:18 GMT

Good Day Again,

I just remembered that I have more to pursue once my glasses come in.

Specifically as Robert said "The accuracy of the frame and lens positioning
is fundamental."

Is this where the knowledge of convergence and parallax is in important?

Thanks in Advance,

Father Times

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Robert Martellaro - 06 Dec 2004 17:50 GMT

>Good Day Again,
>
[quoted text clipped - 8 lines]
>
>Father Times

My point being that you can't get hung up on abbe numbers and lens brands if the
lens is not positioned and designed properly.

Robert

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Robert Martellaro - 06 Dec 2004 19:00 GMT

>Good Day,
>
[quoted text clipped - 19 lines]
>From what I gather, progressive lenses either give you a wide field of view
>for distance or intermediate vision but not both.

There are only minor differences, field of vision wise, between lens brands at
the intermediate and near point. There is probably more of a difference for the
distance peripheral vision but even here the brain compensates quite well.

>My doctors changed my prescription to . . .
>Driving
>Sphere Cyl Axis
>+.5 -.75 90
>+.5 -.1. 94
>Add .75 The optician made the seg hght 17 (35 mm width)

I believe the add here should be +1.50. A seg width of 28mm should be more than
adequate.

>Computer
>Sphere Cyl Axis
>+1 -.75 90
>+1 -.1. 94
>Add .75
>Add .75 The optician made the seg hght 18 (35 mm width)

Depends on the work distances. As I mentioned previously it is not common to Rx
computer glasses with this add power. If the monitor is very close, let's say
19" or so, that's a different story.In that case it might be better to use
single vision readers with the add possibly cut by .25DS.

>Do these prescriptions make sense when compared to his original
>prescription?
>
>They are both CR39 $40
>with Vivx AR $30

That's less than I pay a top quality lab for those items. Even with a discount
for volume they're not making enough to pay for a good clerk let alone an
optician.

>Nathan Flex Titanium $100.

My book shows this to be a stainless steel frame, and an extremely cheap one at
that.

>The frames were the only ones that had the height the optician recommended
>and provided a quasi text book fit. Her assistant weeks earlier had said
>that any height would do for progressives. They will be in two weeks.

Minimum height on a straight top bifocal is about 12mm. A tad higher if there
are frequent close tasks. You could have had a much smaller frame without
compromise.

>Between the two bifocals, I believe that I have four different focal
>distances (two different intermediate distances). Is this correct?

I count three, unless you really want the bifocal on your driving glasses to
have a working distance in the mid 20" range.

>I shopped Wal-Mart, Sam's, BJ's and Costco. My particular Sam's was not
>very knowledgeable. Wal-Mart had both good and bad. BJ's was very honest.
[quoted text clipped - 5 lines]
>avoid polycarbonate and to really know what I am buying.
>My next effort will be for my wife and daughter's glasses.

If you want an extremely stable and warp proof lens surface then you should
choose crown glass. Otherwise any of the other plastics will serve you well with
the Rx that you require.

>Thanks for the wonderful information and I look forward to your additional
>comments.
>
>Father Times

Hope this helps

Robert Martellaro
~~~~~~~~~~~~~~~~~~
Optician/Owner
Roberts Optical
robopt@execpc.com
~~~~~~~~~~~~~~~~~~
"Science is a way of trying not to fool yourself."
- Richard Feynman

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