True about paralytic squint is: March 2010
The core concept here is understanding the pathophysiology and clinical features of paralytic squint. Paralytic squint results from damage to the cranial nerves that control eye movement, such as CN III, IV, or VI. This leads to weakness in the affected muscle, causing misalignment of the eyes. The key features include diplopia (double vision), which is worse when looking in the direction of the paralyzed muscle, and a compensatory head posture to minimize the diplopia.
Now, without the options, I have to think about common distractors. Common incorrect answers might include statements about congenital squint, which is different because it's present from birth and doesn't involve paralysis. Another might be about restrictive disorders like thyroid eye disease, which can mimic paralytic squint but have different causes. Also, confusion with accommodative squint, which is related to focusing rather than muscle function.
The clinical pearl here is that in paralytic squint, the affected eye can't move in the direction of the paralyzed muscle, and the diplopia is typically horizontal or vertical depending on the involved muscle. For example, CN VI palsy would affect the lateral rectus, causing inability to abduct the eye, leading to horizontal diplopia.
Since the options aren't provided, I'll structure the explanation around the core concept, correct answer's reasoning, and why other options might be wrong. The correct answer should emphasize features like acquired etiology, diplopia, and specific cranial nerve involvement. The incorrect options would likely mix up these features with other types of strabismus or unrelated conditions.
I need to make sure the explanation is concise but covers all necessary points. Also, using bold for key terms and structuring each section as per the user's instructions. Let me check the character count to stay within the limit. Alright, I think that's covered.
**Core Concept**
Paralytic squint (paralytic strabismus) arises from **acquired dysfunction of cranial nerves III, IV, or VI**, leading to **extraocular muscle paresis**. It is distinguished from congenital or acquired non-paralytic strabismus by features like **diplopia** and **inability to move the eye in the direction of the affected muscle**.
**Why the Correct Answer is Right**
In paralytic squint, **diplopia is constant and worsens with gaze toward the paralyzed muscle**. For example, a CN VI palsy (lateral rectus palsy) causes **inability to abduct the eye**, resulting in **horizontal diplopia**. The condition is often **acquired** (e.g., due to stroke, trauma, or diabetes) and presents with **compensatory head tilt or turn** to reduce diplopia. Unlike congenital strabism