**Question:** A 20 year old man complains of difficulty in reading the newspaper with his right eye, three weeks after sustaining a gun shot injury to his left eye. The most likely diagnosis is -

A. Diplopia (double vision)
B. Eye muscle paresis (weakness)
C. Corneal ulcer
D. Conjunctival laceration

**Correct Answer:**

**Core Concept:**
The presented scenario involves a patient with a history of gunshot injury to the left eye, presenting with diplopia (double vision) in the right eye. This indicates a neurological problem affecting the ocular motor system, specifically the extraocular muscles, which control eye movements.

**Why the Correct Answer is Right:**
In this case, the patient's right eye is experiencing diplopia, suggesting an issue with the ocular motor system. The ocular motor system controls the movements of the extraocular muscles, which are responsible for the alignment and conjugate movements of the eyes. The patient's problem likely arises from an injury to the left eye, causing a neurological problem that affects the ocular motor system in the right eye.

**Why Each Wrong Option is Incorrect:**

A. **Diplopia (double vision)** is a plausible outcome, but the correct answer focuses on the neurological issue affecting the ocular motor system rather than the primary injury to the left eye itself.

B. **Eye muscle paresis (weakness)** could contribute to diplopia, but the primary focus should be on the neurological issue affecting the ocular motor system, not the muscle weakness.

C. **Corneal ulcer** would present with pain, redness, discharge, and possibly vision loss, not diplopia in the unaffected eye.

D. **Conjunctival laceration** would cause pain, tearing, and possible vision loss, not diplopia in the unaffected eye.

**Clinical Pearl:**
In cases of ocular trauma, it is essential to consider the potential neurological sequelae. Diplopia in the non-injured eye due to trauma to the contralateral (opposite side) eye indicates a neurological issue affecting the ocular motor system, which should prompt further neurological evaluation.