Enophthalmos in dogs and cats: causes to consider
Which of these conditions does NOT cause enophthalmos?
chevron_right Show answer and explanation
A. Horner's syndrome
It does cause it: loss of tone in the orbital smooth muscle (sympathetic innervation) slightly sinks the globe, together with miosis, ptosis and third eyelid protrusion.
B. Severe ocular pain, for example from a corneal ulcer
It does cause it: pain triggers contraction of the retractor bulbi muscle, which actively retracts the globe and makes the third eyelid protrude.
C. Atrophy of the masticatory muscles or loss of orbital fat from cachexia
It does cause it: as the orbital contents lose volume the globe sinks, for example in chronic masticatory myositis or in very thin or elderly animals.
D. Retrobulbar cellulitis or abscess
Correct. A space-occupying lesion behind the globe pushes it forward and causes exophthalmos, not enophthalmos.
lightbulb Key takeaway
Distinguish true enophthalmos from a small globe (congenital microphthalmia or phthisis bulbi after trauma or severe uveitis), which also looks sunken. When enophthalmos comes with third eyelid protrusion, rule out ocular pain with fluorescein before considering Horner's.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.