Oculosympathetic paresis

Because sympathetically innervated smooth muscle fibers also exist in the lower eyelid, oculosympathetic paresis can produce elevation of the lower lid (so-called upside-down ptosis). This condition is often subtle. However, this sign, along with ptosis of the upper lid, contributes to a narrowing of the palpebral fissure, giving the appearance of enophthalmos. 

The term Homer s syndrome is used to refer to any oculosympathetic palsy or paresis. 

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