Pupillary and lacrimation alterations

Due to in-depth neuroanatomical and functional knowledge, the clinical examination of the pupils is considered an indicator of optic nerve conduction, brainstem integrity, vigilance, and coma. The autonomic nervous system regulates pupil size in response to various stimuli. The parasympathetic nervous system causes miosis in response to light and near visual stimuli. The sympathetic nervous system causes mydriasis in the dark and in response to a variety of arousal factors, both physiological such as wakefulness and pathological such as pain. The clinical approach to pupillary abnormalities must focus on the clinical and pharmacological assessment of the pupil's response to light and near stimuli. Observation and quantification of responses to physiological tests can be supplemented with specific pharmacological tests to detect damage to sympathetic or parasympathetic innervation. Local or generalized disorders of the autonomic nervous system, also affect neural control of lacrimation. Abnormal lacrimation can be divided into hypo lacrimation, excessive lacrimation or epiphora, and inappropriate lacrimation. Generalized disorders, including Riley Day syndrome or familial dysautonomia and multisystem atrophy or PAF, will be discussed in the chapter.