At a glance 2 min

Contact lenses that let you zoom in with the blink of an eye

Researchers at the University of San Diego (USA) have just developed a prototype of a soft contact lens that can automatically adjust its focus by detecting the movements of its wearer’s eyes. The contact lens also has a zoom feature which can be activated by blinking.
Contact lenses that let you zoom in with the blink of an eye
Contact lenses that let you zoom in with the blink of an eye

Presented in the journal Advanced Functional Materials, this robotic contact lens is made up of layers of extensible polymers whose structure changes when an electrical current is applied to them, causing them to dilate or contract. In both cases, the lens’ focus changes.

A futuristic contact lens

Simply put, the scientists measured the signals emitted by the eye in an electrooculogram, i.e. data that is generated during specific movements (up, down, left, right, blink, double blink): their flexible biomimetic lens responds directly to this type of electrical impulse and adjusts its focal length based on the signals generated.

The ability to adjust focal length by blinking and following eye movements could compensate defects in the retina by adjusting the focus to nearby objects, such as letters in a book, or distant objects, depending on the user’s needs.

The device’s sensitivity could also be adjusted to detect multiple blinks, which could for instance change the zoom level of the lens: one could simply blink twice to zoom in on an object or detail, and blink twice again to “zoom out”.

A super hero’s eyesight, almost…

Of course, this is a far cry from a super hero’s vision which could detect a detail at a distance of several hundred metres. The term “focus” is in fact more appropriate than “zoom”. Nevertheless, this development could be used, a few years from now, in visual prostheses or adjustable glasses, as well as in the field of remote-controlled robotics. These super lenses could help patients with various vision disorders, and in particular Age-Related Macular Degeneration (ARMD).

The lenses will require a little more development, starting with making the system more user-friendly. For the time being, the system that picks up the electro-oculographic signal generated by the eye’s muscular activity is made up of five electrodes placed around the eye: a little invasive for daily use!

Much electronic miniaturisation work and several years of development will be required before this promising and versatile system will appear on the market.

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