You try on several pairs of eyeglasses to see how the frames
look on you from multiple angles. Only you're not actually
wearing physical glasses but rather examining a lifelike 3D
model of your own head on the iPad.  Or you are indeed wearing
physical glasses. But by turning dials attached to the frame,
you can alter the corrective power of the left and right lens,
without having to consult an eye care professional.  I'm not
outlining some futuristic vision on the state of eyewear. I'm
talking about two new examples of how technology has changed the
way you might purchase specs, not just in the future, but right
now.  I'll focus on each separately.  • app. Right off the bat,
you can probably think of three very good reasons why you might
be reluctant to buy glasses virtually using an iPad. For
starters, you're not sure what the glasses will look like on
you. But you also question how comfortable the frames will be to
wear, and — most critically — how well you'll ultimately be able
to see through them.  With i