**Core Concept**
Siderosis bulbi is a rare condition characterized by the deposition of iron in the intraocular tissues, leading to vision loss. This occurs due to the introduction of iron-containing foreign bodies into the eye.

**Why the Correct Answer is Right**
The correct answer is **C. Iron particles from a blast injury**. Siderosis bulbi typically results from the intravitreal migration of iron-containing foreign bodies, such as shrapnel fragments. The iron particles can cause damage to the retina, choroid, and other intraocular tissues, leading to vision loss. The iron particles can be introduced into the eye through penetrating trauma or during surgery. The pathophysiology involves the breakdown of the iron particles, releasing free iron ions, which then accumulate in the intraocular tissues, causing oxidative stress and inflammation.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because siderosis bulbi is not typically associated with autoimmune disorders. While autoimmune responses can contribute to various eye conditions, siderosis bulbi is a distinct entity caused by the presence of iron-containing foreign bodies.
* **Option B:** This option is incorrect because lens dislocation is not a direct cause of siderosis bulbi. Lens dislocation can occur due to various reasons, including trauma, but it does not directly lead to the deposition of iron in the intraocular tissues.

**Clinical Pearl / High-Yield Fact**
It is essential for ophthalmologists and emergency medicine specialists to be aware of the potential for siderosis bulbi in patients with a history of penetrating trauma or blast injuries. Early detection and removal of iron-containing foreign bodies can prevent vision loss in these patients.

**Correct Answer: C. Iron particles from a blast injury**