Oculomotor apraxia (OMA) is the absence or defect of controlled, voluntary, and purposeful eye movement. It was first described in 1952 by the American ophthalmologist David Glendenning Cogan. People with this condition have difficulty moving their eyes horizontally and moving them quickly. The main difficulty is in saccade initiation, but there is also impaired cancellation of the vestibulo-ocular reflex. Patients have to turn their head in order to compensate for the lack of eye movement initiation in order to follow an object or see objects in their peripheral vision, but they often exceed their target. There is controversy regarding whether OMA should be considered an apraxia, since apraxia is the inability to perform a learned or skilled motor action to command, and saccade initiation is neither a learned nor a skilled action. Symptoms
Absence of fast phase nystagmus on horizontal optokinetic testing
Problems in nerve function involved in eye movement control, called neuropathy
Inability to visually follow objects
Head thrusts to compensate for the inability to accomplish voluntary horizontal gaze. Related developmental problems
Even though OMA is not always associated with developmental issues, children with this condition often have hypotonia, decreased muscle tone, and show developmental delays. Some common delays are seen in speech, reading and motor development

Causes
OMA is a neurological condition. Although some brain imaging studies of people with OMA reveal a normal brain, some MRI studies have revealed unusual appearance of some brain areas, in particular the corpus callosum, cerebellum, and/or fourth ventricle. Oculomotor apraxia can be acquired or congenital.
It is characterized by cerebellar atrophy and peripheral neuropathy. Sufferers of Type 2 have high amounts of another protein called alpha-fetoprotein (AFP), and may also have high amounts of the protein creatine phosphokinase (CPK). Mutations in the SETX gene are the cause of the disease. AOA2 shows cerebellar atrophy, loss of Purkinje cells, and demyelination. In particular, there is a failure of the cerebrocerebellar circuit in AOA2 that has been shown to be responsible for the weaker coordination of complex cognitive functions such as working memory, executive functions, speech, and sequence learning. Although there is no sign of mental retardation or severe dementia, even after long disease duration, research on families with possible AOA2 have shown mild cognitive impairment as indexed by the Mini-Mental State Examination (MMSE) and the Mattis Dementia Rating Scale. These impairments appear to be mostly due to a deficit in initiation and concept subtests,. Ataxia telangiectasia
Telangiectasias are widened blood vessels that can develop anywhere on the skin, mucous membranes, whites of the eyes, and even in the brain. Telangiectasias are associated with multiple systemic signs, the most serious of which are unusual sensitivity to ionizing radiation, excessive chromosomal breakage, and a deficiency in the immune system. Ataxia telangiectasia results from defects in the ataxia telangiectasia mutated gene, which can cause abnormal cell death in various places of the body, including brain areas related to coordinated movement of the eyes. Patients with ataxia telangiectasia have prolonged vertical and horizontal saccade latencies and hypometric saccades, and, although not all, some patients show head thrusts,.