Up to a certain age our eyes can normally adapt to any distance without difficulty. We enjoy clear, focused vision at near, intermediate and long distances. The lens and ciliary muscle in the eye adjust automatically – all totally unnoticed to us.
However, as we get older our eyes experience a steady deterioration in their ability to "accommodate," in other words to switch focus between different viewing distances. Nowadays, the eye is subjected to additional strain due to the frequent and intense use of digital displays. We are confronted with a large amount of information in a small space, and often in tiny lettering. And this situation is further compounded by the need to move our eyes constantly between short and long distances.
As a result, many people then experience eye irritation, headache or neck strain.