What condition is characterized by diplopia on upward gaze and no upward or outward rotation of the eye?

The condition characterized by diplopia on upward gaze and the absence of upward or outward rotation of the eye is cranial nerve III palsy. In cranial nerve III palsy, the oculomotor nerve, which primarily controls eye movement, is impaired. This results in an affected eye that cannot move upwards or outwards. Patients often experience diplopia, particularly when trying to look up, as one eye may remain fixed while the other cannot align properly.

Orbital blowout fractures can lead to restricted eye movements but typically do not present with true CN III palsy symptoms, as the mechanism of injury is different. They may affect the muscles indirectly but are recognized by other signs, such as enophthalmos and potential issues with anatomical structures rather than a specific limitation of upward gaze as seen in CN III palsy.

Retinal detachment primarily affects vision rather than eye movement, manifesting symptoms such as flashes or floaters rather than diplopia or motion restriction.

Optic neuritis affects vision through the optic nerve but also does not specifically present with diplopia related to gaze limitations.

Understanding the nuances of each condition helps clarify why cranial nerve III palsy is the most accurate identification of the symptoms described in the question.