All of the following may be present in Duane’s retraction syndrome except:
**Core Concept**
Duane's retraction syndrome is a congenital ocular motility disorder characterized by limited abduction of the eye, often accompanied by retraction of the eye upon attempted adduction. This condition arises from abnormalities in the development of the sixth cranial nerve (abducens nerve) and surrounding tissues.
**Why the Correct Answer is Right**
The key feature of Duane's retraction syndrome is the inability to abduct the eye (move it outward), which is usually due to a deficiency or abnormality in the lateral rectus muscle, the primary abductor of the eye. The retraction of the eye upon attempted adduction is thought to be due to the unopposed action of the medial rectus muscle, which is responsible for adduction. The presence of a normal or even overactive superior oblique muscle can contribute to the characteristic vertical head tilt seen in some patients with Duane's retraction syndrome.
**Why Each Wrong Option is Incorrect**
**Option A:** This option may be present in Duane's retraction syndrome, as some patients may exhibit a compensatory hypertrophic of the superior oblique muscle, leading to an overactive or even overcorrected vertical deviation.
**Option B:** This option is also consistent with Duane's retraction syndrome, as the condition often presents with a characteristic "abducted" appearance of the eye, with the eye being positioned in an abnormal position due to the limited abduction.
**Option C:** This option may not be present in Duane's retraction syndrome, as the condition typically does not involve a significant deviation of the eye in the vertical plane (upward or downward).
**Clinical Pearl / High-Yield Fact**
In Duane's retraction syndrome, the key to diagnosis is recognizing the characteristic limited abduction of the eye, often accompanied by retraction upon attempted adduction. The presence of a compensatory hypertrophic of the superior oblique muscle can lead to an overactive or even overcorrected vertical deviation.
**Correct Answer:** C.