Better bifocals on the horizon

Wearers of unwieldy bifocal spectacles, take heart. A new kind of lens could offer a neat solution to the problem of switching between two lens types. The electrically powered design can shift from one lens power to another in the blink of an eye, or in this case, the flip of a switch.

This is good news for bifocal and trifocal users, which will include most of us at some point in our lives. Some 90% of people over the age of 45 develop presbyopia, in which the lens loses its flexibility and becomes less able to switch its focus from distant to near objects.

The most common solutions to this affliction are bifocal or trifocal lenses, which are divided into two or three different areas, respectively, each with its own focusing power. However, such glasses limit the field of view and require the user to use a specific area of the lens to see a certain object. Close objects, for example, must be viewed by peering downwards, which can lead to dizziness and headaches. Even varifocal lenses, which feature a gradation in power, require users to raise or lower their gaze to see near or far.

Better bifocals on the horizon - Electrical lenses switch modes at the flick of a switch.