**Core Concept**
Iridocyclitis, also known as anterior uveitis, is an inflammatory condition of the uvea, the middle layer of the eye. The primary goal of treatment is to reduce inflammation, prevent complications, and promote healing.

**Why the Correct Answer is Right**
Corticosteroids, specifically prednisolone, are the first-line treatment for iridocyclitis due to their potent anti-inflammatory effects. They work by inhibiting the release of pro-inflammatory cytokines and mediators, thereby reducing inflammation and preventing tissue damage. In the context of iridocyclitis, corticosteroids help to decrease pain, reduce inflammation, and prevent complications such as cataract formation or secondary glaucoma.

**Why Each Wrong Option is Incorrect**
**Option A:** Atropine is used in the treatment of iridocyclitis to induce cycloplegia and reduce pain, but it is not the primary treatment for inflammation.
**Option B:** Cyclophosphamide is an immunosuppressive agent used in the treatment of certain autoimmune disorders, but it is not the first-line treatment for iridocyclitis.
**Option C:** Acetazolamide is a carbonic anhydrase inhibitor used to reduce intraocular pressure in conditions such as glaucoma, but it is not used to treat iridocyclitis.

**Clinical Pearl / High-Yield Fact**
When treating iridocyclitis, it is essential to use topical corticosteroids with caution, as they can increase the risk of cataract formation and secondary glaucoma. Patients should be monitored closely for these potential complications.

**Correct Answer:** C. Prednisolone.