Presbyopia is the loss of the ability to refocus from distance to near (accomodation) that occurs as we age. In this article, I will take a slightly more technical look at what happens to accommodation as we age. For an introduction to presbyopia, click here. Accomodative Amplitude describes the amount that we can focus from distance to near. It is measured using the unit Diopter. The following table shows how near vision changes as accommodative amplitude is lost: Table

Remember that moment you first couldn’t see something close up? It probably happened suddenly. Maybe you were reading a map in a car at night, or trying to read a text in dim light. Suddenly, it was there. And since that day, your near vision has never been the same. Focusing seems to occur more slowly. You are aware of eye strain. You keep readers around the house or use bifocals. Presbyopia- the loss of accommodation (refocusing) to near vision that occurs as we get ol