20-20-20 Rule for Better Vision
In our modern world, people spend hours on end staring at computer screens, smartphones, tablets, e-readers, and books that require their eyes to maintain close focus.
For most people (all except those who are nearsighted and aren’t wearing their glasses), their eyes’ natural focus point is far in the distance. In order to move that focus point from far to near there is an eye muscle that needs to contract to allow the lens of the eye to change its shape and bring up-close objects into focus. This process is called accommodation.
When we accommodate to view close objects, that eye muscle has to maintain a level of contraction to keep focused on the near object. And that muscle eventually gets tired if we continuously stare at the near object. When it does, it may start to relax a bit and that can cause vision to intermittently blur because the lens shape changes back to its distance focal point and the near object becomes less clear.
Continuing to push the eyes to focus on near objects […]