Vossius ring is seen in
**Core Concept**
Vossius ring is a pathognomonic sign associated with blunt ocular trauma, specifically a subconjunctival hemorrhage caused by a sudden increase in intraocular pressure.
**Why the Correct Answer is Right**
Vossius ring occurs when the increased intraocular pressure forces the conjunctival blood vessels to rupture, resulting in a ring-shaped hemorrhage on the cornea. This phenomenon is thought to be due to the pressure differential between the anterior chamber of the eye and the conjunctiva. The ring typically appears as a circular or semicircular area of ecchymosis on the cornea, often with a clear center. The underlying mechanism involves the sudden increase in intraocular pressure, which disrupts the blood vessels in the conjunctiva, leading to bleeding.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Vossius ring is not associated with penetrating eye injuries, which typically result in a different type of ocular trauma.
**Option B:** This option is incorrect because Vossius ring is not a sign of glaucoma, although increased intraocular pressure is a common factor in both conditions.
**Option C:** This option is incorrect because Vossius ring is not seen in conditions that cause chronic or low-grade eye pressure, such as uveitis or conjunctivitis.
**Clinical Pearl / High-Yield Fact**
In cases of blunt ocular trauma, it is essential to perform a thorough ophthalmic examination, including tonometry to assess intraocular pressure, and to look for signs of Vossius ring, which can help diagnose the underlying mechanism of injury.
**Correct Answer:** C.