Autofocus spectacles?

 

I was intrigued to learn of a new optical technology that allows spectacles to autofocus from near to far vision.

The glasses contain eye-tracking sensors as well as liquid crystals in the lenses, which are used to change the prescription instantaneously. The result, according to the company, is an improvement on current bifocal or varifocal lenses, both of which are meant for people who need assistance seeing both far and close distances, but come with drawbacks.

. . .

By using a dynamic lens, IXI does away with fixed magnification areas: “Modern varifocals have this narrow viewing channel because they’re mixing basically three different lenses,” said Niko Eiden, CEO of IXI. “There is far sight, intermediate and short distance, and you can’t seamlessly blend these lenses. So, there are areas of distortion, the sides of the lenses are quite useless for the user, and then you really have to manage which part of this viewing channel you’re looking at.”

The IXI glasses, Eiden said, will have a much larger “reading” area for close-up vision — although still not as large as the entire lens — and it will also be positioned “in a more optimal place,” based on the user’s standard eye exam. But the biggest plus, Eiden added, is that most of the time, the reading area simply disappears, leaving the main prescription for long distance on the entire lens.

“For seeing far, the difference is really striking, because with varifocals you have to look at the top part of the lens in order to see far. With ours, you have the full lens area to see far — as you were used to when you were slightly younger,” Eden explained, referring to people who had glasses for distance vision from their teens or early adulthood, before starting to also need reading glasses, like most people as they get older.

There's more at the link.

I use reading and computer glasses, with different prescriptions, but don't yet need longer-range lenses.  It would be handy to have a single pair that will autofocus from near (book) to slightly longer (computer) distances on demand.

However, I have questions.

1. How are these glasses powered?  There must be a battery somewhere, and a means to carry the power to the lenses themselves.  What's the life of the battery?  How is it recharged and/or replaced when needed?
2. Can these lenses be incorporated/blended with existing technology that darkens the lens in bright light, and lightens it in darker areas, so that one doesn't need a separate pair of sunglasses?
3. How do the lenses perform in the rain?  Will they be able to compensate for drops of rain on their surface, and still provide clear vision?
4. How secure are they against dust, being dropped, and other hazards?  If scratched, as so many spectacle lenses so often are, can they continue in use, or would they have to be replaced?
5. What will they cost?  I imagine that at first, they'll be a premium product.  I won't be able to buy them online from discount vendors, I'm sure.

All that said, this sounds like a very useful development.

Peter