SERIES EDITOR: PAULETTE M. GILLIG, MD, PhD Professor of Psychiatry, Department of Psychiatry, Boonshoft School of Medicine, Wright State University, Dayton, Ohio
CRANIAL NERVES III, IV, AND VI: Oculomotor Function
by RICHARD D. SANDERS, MD, and PAULETTE MARIE GILLIG, MD, PhD
Dr. Sanders is Associate Professor, Departments of Psychiatry and Neurology,Boonshoft School of Medicine, Wright State University, and Ohio VA Medical Center, Dayton, Ohio; Dr. Gillig is Professor of Psychiatry and Faculty of the Graduate School, Department of Psychiatry, Wright State University, Dayton, Ohio. Psychiatry (Edgemont) 2009;6(11):34–39
Motor activity affecting the direction of gaze, the position of the eyelids, and the size of the pupils are servedby cranial nerves III, IV, and VI. Unusual oculomotor activity is often encountered in psychiatric patients and can be quite informative. Evaluation techniques include casual observation and simple tests that require no equipment in addition to the sophisticated methods used in specialty clinics and research labs. This article reviews pupil size, extraocular movements, nystagmus, lid retraction,lid lag, and ptosis. Beyond screening for diseases and localizing lesions, these tests yield useful information about the individual’s higher cortical function, extrapyramidal motor functioning, and toxic/pharmacologic state.
The general appearance of the eyes often conveys impressions about physical and mental condition. As seen most often in Victorian fiction, closeobservation of the eyes can reveal much about the mental state of healthy adults. We tend to associate sunken eyes, prominent folds beneath the eyes, discoloration beneath the eyes, and conjunctival injection with distress and fatigue. Eyes that are “glazed” (appearing to be unfocused) or reddish (due to conjunctival
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ADDRESS CORRESPONDENCE TO: PauletteGillig, MD, Professor, Dept. of Psychiatry, Boonshoft School of Medicine, Wright State University, 627 S. Edwin C. Moses Blvd., Dayton, OH 45408-1461; E-mail: firstname.lastname@example.org KEY WORDS: psychiatry and neurology; oculomotor; extraocular movements; eye movements; nystagmus; pupil; examination of the visual system; cranial nerve III; cranial nerve IV; cranial nerve VI; oculomotor nerve;trochlear nerve; abducens nerve
injection) elicit suspicions of fatigue and/or the use of intoxicating substances. Spontaneous eye movements also have conventionally accepted implications. A lack of direct eye contact is taken to indicate a lack of confidence, authenticity, or interest; excessive eye contact can be taken as intimidating. Frequent lateral gazes (“shifty eyes”)sometimes implies anxiety or deception, but also may be assumed to reflect hypervigilance, paranoia, or hallucination. Because these features of the eyes can have so many causes, it is more useful to start with specific observations (e.g., frequent, rapid, spontaneous, lateral eye movements) rather than an inference (e.g., appears to be responding to internal stimuli) and then considerexplanations. Cranial nerves III (CNIII) (oculomotor), IV (trochlear), and VI (abducens) control the position of the eyeballs; CNIII influences the position of the eyelids and the size of the pupils. In addition to their value in localizing lesions, these three oculomotor nerves (sensory function is limited to proprioception) can reveal subtle changes in general skeletal and smooth muscle activity. Forexample, even minor weakness in one extraocular muscle can cause diplopia, and the eyelids reveal even mild variations in the activity of skeletal or smooth muscle.1,2 Motor activity controlling the direction of gaze, the elevation of the eyelids, and the size of the pupils also reflect higher cortical activity, and are sensitive to drug effects. As such, they are informative in common psychiatric...