What is Near addition (ADD) on a glasses prescription.....?

Question

.....and does it have anything to do with Distance Acuity or Near Acuity?

Answer 1

You've hit presbyopia. If you are shortsighted (have a significant minus number in your prescription) the add will set it off (in whole or in part) to give you clear close vision. If you are longsighted (with a plus prescription) you may need some further plus to focus close. And someone with a low minus may need a lense for close vision that more than cancels out the minus. It's all about the lens losing the elasticity to focus on reading and other near tasks. And when a woman gets her first add it enhances her sexuality enormously. A girl in glasses is a treasure. But a girl in bi- or vari-focals is something else!

Answer 2

The Near add is the total power needed over the distance prescription to allow you to see clearly up close.  For example, if you needed a

-1.00 to see in the distance and had an add of +2.00, you total reading requirement would be +1.00.  So the add power alone is not sufficient.  You need to know what your distance requirement is, if any, and add the add power to it to get the correct reading power.

Answer 3

It's the power in diopters that you'd need for reading glasses if your eyes didn't need a prescription for distance.   Not much to do with acuity, other than it should be chosen to give you good close vision at the distances you need.

Read up on "presbyopia" if you want to learn more.