But for NASA astronauts working in the near weightlessness of a space environment, it's not that easy.
After all, they're trying to read from all sorts of angles. And many of them are middle-aged and facing presbyopia, that classic "Mom needs reading glasses" condition. Adding insult to injury, the microgravity environment actually helps degrade vision.
Made by Van Nuys, Calif.–based Zoom Focus Eyewear (and sold for $900 per pair, retail), the three millimeter-thick, flexible lenses can change their focus on the fly.
Each TruFocals lens—about three millimeters thick—actually consists of two magnetically attached lenses. The lens closer to the eye is flexible, with a transparent distensible (expandable) membrane attached to a clear rigid surface. The space between the membrane and the clear rigid surface holds a small amount of clear silicon fluid. A sliding lever on the bridge of the eyeglasses is used to push the fluid forward to alter the shape of the membrane and, by extension, the flexible lens. TruFocals for people with more advanced presbyopia contain more fluid than those made for people with a milder form of the condition. The second, outer lens features the wearer's normal prescription.
In other words, the flexible lens replaces the eye's eroding natural ability. That's important because much of what NASA astronauts do -- use complex equipment, read checklists and overhead instrument panels, etc. -- is difficult to do with conventional eyeglasses, which have a small corrective zone.
And astronauts aren't getting any younger, either.
NASA says its plan is to roll adjustable glasses out for use on the next space mission, either from Zoom Focus or Roanoke, Va.-based PixelOptics, which makes electronic adjustable lenses called emPower!.
Now all the astronauts will have to do is figure out how to make Harry Potter-style round lenses stylish.
This post was originally published on Smartplanet.com