The Horner syndrome describes a complex of symptoms consisting of miosis, ptosis, and enophtalsmus (specifically: pseudoenophtalmus), due to a number of reasons.It is usually caused by paralysis of the sympathetically innervated smooth muscles of the eyes. This can be due to Trauma, infections of the brain steam, pancoast-tumors and lesions to the stellate ganglion.
It is defined by the following three symptoms:
Novel reports describe the enophtalmus to be an artefact of the present ptosis which causes the bulb to sink.Source: Nautiyal A, Singh S, DiSalle M, O'Sullivan J (2005) Painful Horner Syndrome as a Harbinger of Silent Carotid Dissection. PLoS Med 2(1): e19 doi:10.1371/journal.pmed.0020019