Presbyopic Near Vision Mask Correction

Quentin Bennett · Issue 79, Jul/Aug 2014 · pp. 39–42

From our early forties our ability to see things close to us deteriorates considerably in a process known as presbyopia. This deterioration is even more noticeable in the darker conditions prevalent underwater, particularly in our non-tropical climes with their darker and murkier waters. The consequentially larger pupils make the effects of presbyopia even more obvious. I noticed the deterioration whilst diving long before I noticed it in normal life. Do understand that underwater, with wider pupils, the f stop of the eye is open, and consequently the depth of field is greatly reduced. This truly reveals that lessened ability to focus closely. On land generally there are three ways to correct presbyopia : by using single vision near reading lenses, bifocals, or progressive lenses. Progressive lenses usually have the advantage that by using different areas of the lens corridor one can get…