## **Core Concept**
The question tests the understanding of ocular trauma and its complications, specifically hyphaema. Hyphaema refers to the accumulation of blood in the anterior chamber of the eye, often resulting from trauma. The key to answering this question lies in identifying the most likely source of bleeding in the context of a blunt ocular injury.

## **Why the Correct Answer is Right**
The correct answer, **C. Iris vessels**, is the most plausible source of bleeding in this scenario. In a blunt ocular injury, such as being hit with a tennis ball, the force of the impact can cause damage to the iris vessels. The iris is richly vascularized, and a blunt trauma can disrupt these vessels, leading to bleeding into the anterior chamber, which is observed as hyphaema. The fact that there is no perforation but hyphaema suggests that the injury did not penetrate the eye but was severe enough to cause internal damage.

## **Why Each Wrong Option is Incorrect**
- **Option A:** A. Ciliary body - While the ciliary body can be a source of bleeding in ocular trauma, it is less commonly associated with blunt trauma causing hyphaema compared to iris vessels. The ciliary body is more involved in the production of aqueous humor and is not the primary site of vascular damage leading to hyphaema in this context.
- **Option B:** B. Choroidal vessels - Choroidal vessels are located in the posterior segment of the eye and are less likely to be directly involved in blunt trauma leading to hyphaema. Bleeding from choroidal vessels would more likely result in vitreous hemorrhage rather than hyphaema.
- **Option D:** D. Retinal vessels - Retinal vessels are also located in the posterior segment and are not a direct source of bleeding into the anterior chamber. Damage to retinal vessels would more likely result in complications such as vitreous hemorrhage or retinal detachment.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that hyphaema is a serious complication of ocular trauma and requires prompt evaluation and management to prevent complications such as secondary glaucoma, corneal blood staining, and vision loss. The presence of hyphaema necessitates careful follow-up and possible intervention to control intraocular pressure and address the source of bleeding.

## **Correct Answer:** C. Iris vessels