**Core Concept**
Busacca nodules are a type of inflammatory nodule found in the iris, specifically near the collarette, which is the transition zone between the iris stroma and the iris pigment epithelium. These nodules are associated with granulomatous inflammation and are often seen in conditions like sarcoidosis, Behçet's disease, or sympathetic ophthalmia.

**Why the Correct Answer is Right**
Busacca nodules are characterized by the presence of granulomatous inflammation, which involves the aggregation of immune cells like macrophages, T lymphocytes, and epithelioid cells. This type of inflammation is typically seen in response to chronic antigenic stimulation. The nodules are usually located near the collarette, where the iris stroma and pigment epithelium meet, and can cause iris thickening and neovascularization. The development of Busacca nodules is thought to be mediated by the release of cytokines and growth factors, which promote the proliferation of fibroblasts and the formation of granulomas.

**Why Each Wrong Option is Incorrect**
**Option B:** Koeppe's nodules are actually a type of nodular inflammation found at the pupillary margin, not near the collarette. They are often associated with conditions like tuberculosis or sarcoidosis.
**Option C:** Lisch nodules are melanocytic hamartomas found in the iris, typically in patients with neurofibromatosis type 1. They are not associated with granulomatous inflammation and are usually not located near the collarette.
**Option D:** Dalen-Fuchs nodules are a type of epithelioid cell collection found in the suprachoroidal space, often in response to conditions like sympathetic ophthalmia. While they are an inflammatory response, they are not typically found near the collarette.

**Clinical Pearl / High-Yield Fact**
When examining the iris for signs of inflammation, it's essential to note the location and characteristics of any nodules or lesions. Busacca nodules are a classic sign of granulomatous inflammation, and their presence can help narrow down the differential diagnosis for conditions like sarcoidosis or sympathetic ophthalmia.

**✓ Correct Answer: A. Busacca nodules**