Accommodative insufficiency refers to an eye's lack of visual accommodation for a near focus. Visual accommodation is the process by which the lens and pupils of the eyes change in order to focus on near and far objects. As people grow older their eyes become less flexible and less able to properly focus on the image that eye is seeing. When this happens the eye is unable to send a sharp and accurate image to the brain. This is the description of what happens in cases of near-sightedness.