Pentagon Orders Dual-Focus Contact Lens Prototypes 41
New submitter cb_is_cool writes "From the Beeb: 'The Pentagon has put in an order for prototype contact lenses that give users a much wider field of vision. The lenses are designed to be paired with compact heads up display units — glasses that allow images to be projected onto their lenses.' Hopefully, any mugger within 50 yards will have a red status bar above his head. 'The central part of each lens sends light from the HUD towards the middle of the pupil, while the outer part sends light from the surrounding environment to the pupil's rim. The retina receives each image in focus, at the same time."
NO THANK YOU. (Score:5, Interesting)
Dual-focus lenses like do produce sharp images at multiple focal ranges (or, in this case, from multiple sources) -- but they also produce blurred images at every focal range. So, you see a sharp image, but with halos around bright objects, and no way to mask them out. If you have to look at a white-on-black display, or a glowing readout in the dark, you're in for a real treat.
We already know how to integrate optics so your HUD shows things at a neutral focal distance. With holographic optics, we ought to be able to make such optics lightweight and compact enough for anyone's tastes. So why "correct" the eye to super-nearsightedness?
This seems like a solution to the wrong problem.
Seems similar to today's multi-focal IOL (Score:5, Interesting)
FWIW: The standard IOL (inter-ocular lenses) that you get today if you have cataract surgery are generally of one focal length (mono-focal) and usually selected for far vision. Since IOLs are not attached to your squinting/focusing muscles so you pretty much need reading glasses to look at anything close up after you get them. However, there also exists today some multi-focal IOLs that seem like they work on a similar principle to the described contact lens.
FYI, the current generation of multi-focal IOLs have an inner region (focused to near-er objects) and one or more annulus regions (focusing on progressively farther objects). When the pupil is mostly closed (reading in bright light), you only see through the center of the lens allowing fairly clear near vision, but when your pupil is more dialated (when say outside, or in a dimly lit room) say you get images from one or more of the annulus regions which dominate the light received and are focused farther. It isn't a perfect solution as patients often initially see halos from the multi-focal parts, but apparently your brain apparently eventually learns to "filter" this out. There are better multi-focal IOLs in development (that allow for actual focus accommodation with eye muscles), but this is the common multi-focal case today.
With this scheme, it seems that the described contact lenses would have similar effect of the multi-focal IOL in its dialated pupil/far focus configuration except of course instead of part of the image originating from a near focus and thus blurry in the IOL case, would be replaced by a close distance Heads-up display and in clear focys on the retina. Seems like it might work just fine.
Of course with a contact lens like in the article, you can always take it off. With a multi-focal IOL, you are stuck with this all the time. On the other hand,100-of-thousands of folks have multi-focal IOLs for their cataract replacement and they voluntarily have this kind of stuff permanently sewn in their eyes, so there's no reason to think this won't just work.