Sola Access for near -> mid only?

A friend (-6 with a 2.5 add for reading) is trying some Sola Access
lenses which are for near- to -middle distance only. The doc explained
that there is a maximum variation between the nearest and furthest
settings of 1.5D. The friend's wife is nearsighted, but less so and
with a less than 1.5D add. Friend wondered if she could get Access
lenses that would work for both near and far. The doc said no. The
friend (Caltech grad and instructor) asked if the reason was optical or
biological. The doc said it was optical but couldn't explain it.

Any explanation?

--
Cheers,
Bev
======================================================================
"Steve Balmer, CEO of Microsoft[0], recently referred to LINUX as a
cancer. Unsurprisingly, that's incorrect; LINUX was released on August
25th, 1991 and is therefore a virgo." -- Kevin L

 

Why would anyone want to do that instead of regular progressives?

My guess is that the far vision would not be as good as a normal progressive
and would not be as suitable for driving. This would probably be manifested
in the poorer peripheral vision at far distances needed to achieve a wider
transition area. But that is just a guess.

 

Do what, have near+mid progressives? If you spend most of your time
inside and/or using a computer and only use distance vision for driving,
it makes perfect sense. The Access lenses provide a wider field of good
focus than ordinary progressives, which is why his wife wants them.

Would that make more sense to me if I'd actually used progressives?

 

Access lenses are not for far, they are for mid and near, your friend's wife
will not see clearly at far with them. If she wants far and near, she needs
a regular progressive or bifocal.

With acccess type lenses while looking straight ahead, the computer will be
clear. When looking down, near print ie books, papers, invoices will be
clear. By tipping the chin down and directing eyes upwards, the bulletin
board and faces of people coming in your door will be clear. The clock
across the room and the view out the window will be blurred though, with no
spot on the lens getting them clear.

To understand this lens design, draw a circle on a piece of paper to
represent the lens. Now draw a small arc cutting through the top of the
circle like a smile, with the deepest part of the arc about 1/8 the diameter
of the circle. Repeat with a similar arc (frowning this time), on the
bottom. The large middle area of the circle will have the midrange power,
about +1.50 add. The top arc area is the "far" portion, but will only be
good out to about 6 to 8 ft, similar to +0.50 add. The bottom area is the
"near" portion, similar to +2.00or +2.25 add. The difference between +0.50
distance and +2.00 near gives the 1.50 variation.

Your friend's wife could have the Access set so that the top was equivalent
to her distance, the middle to +1.00 add and near to +1.50 add but I would
be willing to bet large sums that she would not be happy with the quality of
the distance vision. If her add is less than 1.50, she can likely use a
computer with her distance glasses, setting it a little further out at say
30 inches instead of 22, or see distance indoors (6 to 10 ft) with single
vision readers; either of those options would be simpler, easier to use and
less expensive than Access type lens.

Dr Judy

 

The large field of good vision in the Access is set for mid range, not
distance or near. The largest field of vision would be with single vision
mid range glasses, and with your friend's wife having an add of less than
+1.50, the near would be good through them and the distance not too badly
blurred.

Using a regular bifocal or progressive with the top portion set to mid range
and bottom portion set to near is a viable option for computer users.

The Access lens is not for outdoor use, no one should attempt to drive with
it and users are clearly told this.

Dr Judy

 

Thanks, both messages have been forwarded to the friend.