Which feature is commonly present in orbital cellulitis but not in preseptal cellulitis?

Ophthalmoplegia is a hallmark feature of orbital cellulitis that distinguishes it from preseptal cellulitis. In orbital cellulitis, the infection spreads to the orbital space behind the orbital septum, often affecting the extraocular muscles and leading to impaired eye movement, which is referred to as ophthalmoplegia. This condition can present with symptoms such as diplopia (double vision) or limited movement of the eye, indicating that the infection has compromised the function of the structures within the orbit.

In contrast, preseptal cellulitis, which is an infection confined to the anterior portion of the eyelid and surrounding tissues, typically does not involve the extraocular muscles or the orbital contents and, therefore, does not present with ophthalmoplegia. While fever, eyelid erythema, and eyelid edema can occur in both conditions, ophthalmoplegia is specific to orbital cellulitis due to its deeper involvement in the eye structure.