Slab Off for achieving fused image for anisometropia

We ever got orders requiring Slab Off, and we are always concerning on customers’ requirement.
Good news that we just installed option of Slab Off in our lab, to support for patients’ orders when there is need on it.

A fact is that when wearing progressive lenses, the more the wearer needs to look down the higher those prismatic effects. And if the wearer has unequal lens power (anisometropia) bigger than 1.50D, he may get blurry vision, double vision, or it feels very tense.

As shown in below pictures, 2# picture tells when seeing from down position the images from two lenses of different power would be different, and such difference causes unfused images in eyes; 3# picture tells how prism lens works; and 4# picture tells fused image is achieved when adding prism lens.

So if problems of blurry vision or double vision occur with anisometropia, the optician will set a lens with compensation into the frame, as shown in 3#&4# pictures.
And our solution is producing it by freeform grinding to add Slab Off prism on the progressive lenses. The standard Slab off will be found in the stronger minus or weaker plus lens.

We shall note that Slab Off results in a distortion zone and a band of blurred vision, typically between 3-7 mm depending on the level of control and performance we can apply to the machines.

*Compare of back surface of Slab off lens and regular lens.

*Position of Slab off zone.

We hope that after wearing Slab Off the customer would directly respond with a relaxed face or with the sentence “Wow, this feels good” or “I was able to read it out before but it was stressful. Now it is more even” or in extreme cases: ”Double vision is gone! Finally I have one picture again.”

Welcome to contact us for further detail information.
https://www.universeoptical.com/rx-lens/