What is a Focusing Problem?

We must refocus our eyes when we look from one distance to another. Most people are unaware of this change in focus because our visual system typically operates very efficiently and objects always appear in focus. In reality, a focusing adjustment is made every time we look from one place to another with the help of the ciliary muscle. The medical term for this is accommodation.
When a child looks from the board to her desk, she must contract or tighten this muscle. This causes the lens of the eye to change shape and allow the child to see print clearly. When the child looks back to the board, the focusing muscle must then relax to see clearly in the distance.

Problems with the focusing system occur when an individual is unable to quickly or accurately contract or relax the focusing muscle, or if the muscle contraction cannot be maintained for an adequate period of time while completing reading or other near work. Focusing problems can cause headaches, blurry vision when switching focus locations, eye strain, and uncomfortable vision while completing near work.

A focusing problem looks like this: