**Core Concept**
Phlyctenular conjunctivitis is an immune-mediated inflammatory condition characterized by the formation of small nodules on the conjunctiva, often associated with a hypersensitivity reaction to bacterial antigens, particularly staphylococcal. The underlying pathophysiology involves a cell-mediated immune response, with T-lymphocytes playing a crucial role in the inflammation process.

**Why the Correct Answer is Right**
Topical steroids are the mainstay of treatment for phlyctenular conjunctivitis due to their potent anti-inflammatory effects, which help to reduce the immune-mediated inflammation and prevent further tissue damage. By suppressing the immune response, topical steroids can alleviate symptoms and promote resolution of the condition. The exact mechanism of action involves the inhibition of various pro-inflammatory cytokines and enzymes, including cyclooxygenase-2 (COX-2) and lipoxygenase, which contribute to the inflammatory cascade.

**Why Each Wrong Option is Incorrect**
**Option A:** Systemic steroids are generally not recommended for the treatment of phlyctenular conjunctivitis due to their potential for systemic side effects and the availability of more targeted topical treatments.
**Option C:** Antibiotics may be used in cases where a bacterial infection is suspected, but they are not the primary treatment for phlyctenular conjunctivitis, which is an immune-mediated condition.
**Option D:** Miotics are used to treat conditions such as glaucoma and are not indicated for the treatment of phlyctenular conjunctivitis.

**Clinical Pearl / High-Yield Fact**
Topical steroids should be used with caution in patients with a history of glaucoma, as they can increase intraocular pressure. It is essential to monitor patients on topical steroids for signs of glaucoma, such as increased eye pressure or vision changes.

**✓ Correct Answer: B. Topical steroids**