Prescription eyeglasses with an adjustable focal point are also known as “adjustable focus eyeglasses”. By supplying changeable focusing it compensate refractive errors (like presbyopia), letting users to correct them for preferred distance or prescription, or both.
What does this mean? You’ve got eyeglasses that can change focus on the fly! You can finally borrow a friend’s eyeglasses and wear it to look cool and smart without the subsequent headache after being pretentious.
The present Bifocals and progressive lenses are not dynamic but static, it means the user has to adjust their eye angle to look through the portion of the lens with the strong focal point corresponding to the space of the object. This means the user will look through the top part of the lens for far objects and user will look down through the bottom part of the lens for nearer objects. Without having to change where one is looking, this is one characteristic of the adjustable eyeglasses even if it only has one focal length.
Adjustable eyeglasses are now usually used to provide cheap glasses for third world countries, or used to treat presbyopia. So grab one because this can be bought on a cheap!
Near-vision correction is reached over the whole field of view, in any point, not like with common spectacles. Re-adjusting the lens for distance is made to correct distance vision, instead of by tilting and/or rotating the view object through the best part of the lens for the distance. It is very important for astronauts who often have to look above them at monitors. The adjustable glasses let them look up without tilting their heads back too much. Adjustable focus bifocals, like single-focus lenses, also decrease image-jump and spatial deformation in the line of sight connected with conventional multi-focal lenses. In addition, the perfect near-vision correction can be actualized with accuracy, because the variable lenses imitate the focusing action of the young (non-presbyopic) eye.
The disadvantage of adjustable focus mechanism is, it is controlled by a device located on the glasses that requires correcting every once in a while if the user wants to change from seeing near to far (or vice versa).
If you are not able to understand the technicalities that I just blabbered, watch Josh Silver’s demonstration below. Josh Silver is the creator of such technology and he is pretty passionate about this one.