Distance good, reading good, intermediate bad. A progressive puzzle.
I have a patient, let's call him Stan. He's presented me with a poser.
Here's his old RX from May 2009:
-1.75 -0.75 x082 +2.50
-2.00 -0.75 x099 +2.50
Varilux Comfort, Poly, Transitions Grey, Crizal Avance. Vertical alignment is perfect, OS OC is just a touch wide, but well within tolerance.
Here's his new RX from December 2011:
-1.25 -0.75 x073 +2.50
-1.50 -0.75 x097 +2.50
Varilux Comfort 2DRx, Poly, Transitions Grey, Crizal Avance.Vertical and horizontal alignment are spot-on.
So my excellent doctor pulled his distance RX back a bit and I put him in a progressive with a wider reading and intermediate area. But Stan is having problems. He is complaining that his distance is clear, his reading is clear, but his intermediate is too hard to find the focus in. He's coming in today for a new refraction. The only substantial change from the old lenses to the new is that sphere power change, but I have a hard time imagining that that would affect his intermediate and not his distance or near.
I have to admit to being a bit stumped. He's worn a nearly-identical PAL design for years, so I can't think that's the problem. His add hasn't changed, nor has his cylinder changed appreciably. I wanted to throw the problem out to my OB homeys today. He comes in at 420 this afternoon (EST). Any thoughts?
The intermediat is narrow.....the power increases fast ...................
It is very simple ............at a 2.50 add the patient is in another category --------> old, older or real old.
The intermediat is narrow.....the power increases fast and the head position has to move little by little to find the right spot. Many of the old people do have mobility problems, the head bent forward and lots more.
They do not care that much anymore about wearing PALs, as the first hand choice of PALS is to make you look younger, but at a 2.50 add the face is seeded with wrinkles, so put them in a flat top and you will see they will be happy customers.
At the end they are still all the same ...............................
Quote:
Originally Posted by
sharpstick777
This is really a lens design issue, not an RX issue. You may want to consider another lens.
That is the perfect answer and solution for this thread. PALs are PALs and they have their limits even if the manufacturers design and redesign the power and distortion areas can not be overcome. At the end they are still all the same with tiny small differences, but they fetch a mighty dollar and that is why we have to move them.