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Enophthalmos is not Present in Horner Syndrome

Posted by plosmedicine on 30 Mar 2009 at 23:40 GMT

Author: Robert Daroff
Position: Professor of Neurology
Institution: CASE School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
Submitted Date: March 09, 2005
Published Date: March 9, 2005
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

The Case Report by Nautiyal et al [1] is an instructive reminder that the first episode of an acute painful Horner Syndrome should prompt imaging of the ipsilateral internal carotid artery, since carotid dissection (as well as other conditions, such as high grade stenosis) needs to be ruled out. Unfortunately, the authors perpetuate the extremely common misconception that enophthalmos accompanies ptosis and miosis in human Horner Syndrome. It is only an illusion of enophthalmos caused by the ptosis. This is evident in the left eye of their patient in Figure 1.

Actual measurement with exophthalmometry clearly demonstrates the lack of enophthalmos. As stated by Loewenfeld [2], "Animals such as cats, rats, or dogs have enophthalmos on the side of sympathetic lesion. But in man, the enophthalmos is only apparent. The small palpebral fissure makes the eye look sunken in on the affected side, but the position of the globe in the orbit remains virtually unchanged. This has been found by all workers who have measured the supposed enophthalmos objectively." Four supportive references are cited.

Thompson and Miller [3] provide four additional references that the enophthalmos "is apparent rather than real."


1. Nautiyal A, Singh S, DiSalle M, O'Sullivan J (2005) Painful Horner syndrome as a harbinger of silent carotid dissection. PLoS Med 2:0041/e27/e32.

2. Loewenfeld I (1999) The Pupil: Anatomy, Physiology, and Clinical Applications. Boston: Butterworth-Heinemann, Vol. 1, page 1139.

3. Thompson H, Miller N (1998) Disorders of pupillary function, accommodation, and lacrimation. In: Miller N, Newman N, editors. Walsh and Hoyt's Clinical Neuro-ophthalmology, Vol. 1, 5th Edition. Baltimore: Williams & Wilkins, page 964.

No competing interests declared.