Features of Homer’s syndrome include all of the following except :
**Core Concept**
Homer's syndrome, also known as Horner's syndrome, is a group of symptoms that occur due to disruption of the sympathetic nervous system, particularly affecting the oculosympathetic pathway, which controls pupil dilation, eyelid elevation, and facial sweating.
**Why the Correct Answer is Right**
The characteristic features of Homer's syndrome include ptosis (drooping eyelid), miosis (constricted pupil), and anhidrosis (absence of sweating) on the affected side of the face. These symptoms occur due to the loss of sympathetic innervation to the eye and face. The oculosympathetic pathway, which includes the superior cervical ganglion, the cavernous sinus, and the ciliary ganglion, is responsible for these symptoms.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because enophthalmos (sunken eye) is a feature of Homer's syndrome, resulting from the loss of sympathetic tone to the orbital smooth muscle.
**Option B:** This option is incorrect because heterochromia iridum (unequal iris color) can be a feature of chronic Homer's syndrome, especially in congenital cases.
**Option C:** This option is incorrect because decreased corneal sensitivity is not a typical feature of Homer's syndrome.
**Clinical Pearl / High-Yield Fact**
In Homer's syndrome, the affected pupil will constrict when exposed to light (light-near dissociation) due to loss of sympathetic innervation.
**Correct Answer: D.**