There is a dreaded process called "presbyopia" which begins to take effect on most people in their early to mid-40s. It's the loss of focusing power for near vision, causing you to start doing the trombone action with the menu as you attempt to order at a restaurant.
When the eye focuses on a near object, there is a lens that flexes and effectively adds focusing power to the eye. That lens flexes due to a muscle that controls its shape.
A combination of the lens not being as flexible and the muscle not contracting properly leads to this loss of focusing power. Unfortunately, no one has discovered a way to keep that muscle working and the lens flexing.
Until one of you helps me come up with a treatment to reverse or halt that process (and we become multimillionaires), we're stuck with needing reading glasses once presbyopia sets in.
For those people who still have good distance vision, correction is only needed for reading.
There is then a choice to be made: put on reading glasses and then take them off every time you look far away, or wear a bifocal so you can look through the top when viewing distant objects and through the bottom for near objects.
There is no perfect solution, as some people find it frustrating to take reading glasses on and off all day and carry them around everywhere.
Other people have tried bifocals (or trifocals or progressive lenses) and are unable to adapt to them.
There are now "smart glasses" in the works that would solve the above issue of reading glasses vs. bifocals. The prototype was developed at the University of Utah.
These glasses have a clear, flexible membrane controlled by three actuators that flex the membrane according to what distance you are viewing. This lens can change focus in 14 milliseconds.
In the frame's bridge is a device that measures the distance you are viewing via infrared pulses. The distance is then conveyed to the actuators, which control the lens.
There is a rechargeable battery that can last up to 24 hours. I am sure it will be difficult to get the bulk size of the frame down, let alone the price tag, and I can already imagine some possible technological snags. Regardless, it will be a few years before these make it to the consumer market (if they even do).
Keep an EYE out! Who knows what they'll come up with next.
Caroline Bundrick, O.D. is an optometrist practicing at Darling Eye Center, with offices in Bluffton and on Hilton Head Island.