This has come up many times in the exam; the college loves to throw pictures of divergent eyeballs at the candidate, asking them to generate differentials. However, this chapter does not serve as the best resource for answering them.
Examples include:
However, this chapter does not serve as the best resource for answering them. The nerve-specific chapters listed above are better for exam revision. This chapter only brings together the information into one big table, so that it is available in one spot. The best offsite resource for this, which consolidates several textbooks worth of information into one article, is a piece by M.Karatas from the European Journal of Neurology (2009). One should get access to this article - one way or another.
Because this is a "brief summary", I have restrained myself from presenting ridiculously detailed diagrams of the neural pathways responsible for the generation of the sustained conjugate gaze and saccadic eye movement. Instead, you find below a table which only describes the pathology and its clinical features. Generally speaking, a thorough understanding of this fascinating topic is not required for the fellowship exam; it is sufficiently complex to require a long time to process, but is sufficiently rare to yield very few marks per unit of effort. The time-poor candidate may excuse themselves from the reading of the rest of this chapter.
Disorder |
Clinical features |
Location of lesion |
Possible causes |
Internuclear ophthalmoplegia |
(i.e. looks like a 6th nerve palsy, but with nystagmus of the "good" eye)
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Unilateral lesion:
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"One and a half" syndrome |
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Horisontal gaze palsies |
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Vertical gaze palsies |
Upward gaze palsy:
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Downward gaze palsy:
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Total ophthalmoplegia |
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Tonic gaze deviation |
Horisontal deviation
(see Question 24.4 from the first paper of 2009) |
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Sustained upward gaze deviation
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Sustained downward gaze deviation
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The LITFL summary of cranial nerve lesions is without peer in terms of useful information density.
Walker, H. Kenneth, W. Dallas Hall, and J. Willis Hurst. "Clinical methods." (1990).
Karatas, M. "Internuclear and supranuclear disorders of eye movements: clinical features and causes." European Journal of Neurology 16.12 (2009): 1265-1277.
This one is not available as free fulltext, but it's that good that you should travel through the rain and snow to your local medical library to get a hold of it.
Baloh, R. W., J. M. Furman, and R. D. Yee. "Dorsal midbrain syndrome Clinical and oculographic findings." Neurology 35.1 (1985): 54-54.
Warren, Naomi M., and David J. Burn. "Progressive supranuclear palsy."Practical neurology 7.1 (2007): 16-23.
Marco Mumenthaler, Heinrich Mattle "Fundamentals of Neurology: An Illustrated Guide" vis Google Books. Georg Thieme Verlag, 2000.