**Core Concept**
Chronic dacryocystitis is a persistent inflammation of the lacrimal sac and nasolacrimal duct, often due to nasolacrimal duct obstruction. Effective treatment involves addressing this obstruction and reducing inflammation.

**Why the Correct Answer is Right**
The correct treatment for chronic dacryocystitis involves probing and irrigation of the nasolacrimal duct to clear any blockages. This procedure, often performed under general anesthesia or local anesthesia with sedation, helps restore normal tear flow and reduces symptoms of chronic dacryocystitis. The procedure may involve the use of a flexible nasolacrimal duct probe or a bicanalicular silicone tube to facilitate tear drainage.

**Why Each Wrong Option is Incorrect**
**Option A:** Antibiotic therapy alone is not sufficient to treat chronic dacryocystitis, as the condition is often due to a mechanical blockage rather than a bacterial infection.
**Option B:** Dacryocystorhinostomy (DCR) is a surgical procedure that creates a new pathway for tear drainage from the lacrimal sac to the nasal cavity. While it is an effective treatment for chronic dacryocystitis, it is typically reserved for cases where conservative management has failed.
**Option C:** Orbital radiation therapy is not a standard treatment for chronic dacryocystitis, and its use would be unusual in this context.

**Clinical Pearl / High-Yield Fact**
In cases of chronic dacryocystitis, probing and irrigation of the nasolacrimal duct can be a highly effective treatment, but it requires careful patient selection and may need to be repeated if the initial blockage is not fully cleared.

**Correct Answer: C. Dacryocystorhinostomy (DCR) is a surgical procedure that creates a new pathway for tear drainage from the lacrimal sac to the nasal cavity.**