wrap frame causes perception problem

[jofelk]

We made lenses for in an Adidas 123 Gazelle insert. The account gave the lenses to the patient who said he could not wear them. The problem is depth perception, example: the patient has trouble reaching for a pen on the table. This paticular frame is a wrap with Rx insert. We made the lenses in poly stock which has a 2 base, remade in poly with his old base of 4, then remade again in CR-39. Same problem with all lenses. I am not familiar with the lenses in front of the wrap, light stabilizing polarized ? Could the wrap in front of the insert be causing a problem ? Wearing same Rx in a drill, no problems.

Rx is:
OD -4.50 SPH
OS -2.00 -0.25 165

[Spexvet]

I wear those, and my "perception" is different when I put them on. I think it is the wrap of the lenses. I took off the "shield" lenses, and looking through just the clear lenses (a very attractive look, I must add) the effect was the same.

There's a great article in the April 2005 20/20 about wrap, and I'm not talking P Diddy! Check it out.

[eyecare4U]

I might help to use Aspheric lenses with prism.

[drk]

I might help to use Aspheric lenses with prism.

Never use aspheric lenses with prism! (I don't know why that's true, though.)

There are so many places this Rx could go wrong!

First of all, its aniso, but you noticed that.

The insert has too much faceform to be comfortable, but you're stuck with the curvature. This is not the typical "wrap" lens issue, because it's a corrected curve lens in an extra-curvy frame, not an extra-curvy lens in an extra-curvy frame.

Adidas says you should decenter the optical centers by 1mm or something ridiculous.

The point is that the Rx is only correct with a normal front curve on the frame. The patient is looking though the lens at an incorrect angle. You would need to grind the lenses at a compensated Rx, but it takes a complicated formula.

If you private message me, I will give you a first-order approximation of the compensated Rx and prism, but remember that this is difficult even for balanced Rx's. This may be futile, ultimately.

[Bev Heishman]

There is a very good CE article in 20/20 magazine at this time specifically on wrap eye wear. Read it and see if it has any answers. You may need to compensate the Rx in the as worn position and add prism as discussed to make it work.

[Spexvet]

Hey Bev,
You don't read my posts?

[Bev Heishman]

:hammer: :hammer: Sorry Sweetie! I didn't read your post thoroughly. Forgive me!

That article is very good.

Forgive me!

[jofelk]

I know the problems that a wrap can cause, but the lenses in this particular frame are not "wrapped", they are in an insert that fits behind the wrapped front. The insert appears to be held in the frame at the same distance from the eye that a normal set of lenses would be held in a conventional frame. Maybe looking through two sets of lenses, the Rx insert and the wrapped polarized front, is causing a problem?

[Spexvet]

Maybe looking through two sets of lenses, the Rx insert and the wrapped polarized front, is causing a problem?

Take the sun lenses off (easy enough) and have the patient look through just the insert, mounted in the frame. If the issue remains, you've eliminated the "looking through two sets of lenses" variable.