Eye–hand coordination has been studied in activities as diverse as the movement of solid objects such as wooden blocks, archery, sporting performance, music reading, computer gaming, copy-typing, and even tea-making.
It is part of the mechanisms of performing everyday tasks; in its absence, most people would not be able to carry out even the simplest of actions such as picking up a book from a table.
[3] Furthermore, the eyes provide initial information of the object, including its size, shape, and possibly grasping sites for judging the force the fingertips need to exert to engage in a task.
[5] In high accuracy tasks, when acting on greater amounts of visual stimuli, the time it takes to plan and execute movement increases linearly, for example when using a computer mouse, per Fitts's law.
[6] Humans have the ability to aim eye movement toward the hand without vision, using the sense of proprioception, with only minor errors related to internal knowledge of limb position.
This has been attributed to the general degeneration of the cortex, resulting in a loss of the ability to compute visual inputs and relate them to hand movements.
[citation needed] Bálint's syndrome is characterized by a complete lack of eye–hand coordination and has been demonstrated to occur in isolation to optic ataxia.
Although similar to optic ataxia, its effects are more severe and do not necessarily come from damage to the brain, but may arise from genetic defects or tissue degeneration.
[13] Optic ataxia has been often considered to be a high-level impairment of hand–eye coordination resulting from a cascade of failures in the sensory to motor transformations in the posterior parietal cortex.