Okay, I need to figure out the answer to this question about Koeppe nodules. The question is asking where they are located. Let me start by recalling what I know about Koeppe nodules.

First, I remember that Koeppe nodules are related to the eye, specifically the anterior chamber. They are a type of granulomatous inflammation. Wait, granulomatous uveitis is associated with conditions like sarcoidosis, tuberculosis, or syphilis. Now, the location... Koeppe nodules are small, elevated, yellow-white nodules. I think they are found on the iris or the ciliary body.

Wait, the iris is part of the anterior uvea. The ciliary body is also part of the uvea, but maybe the nodules are located in the anterior part of the iris. Let me cross-check. Koeppe nodules are typically located at the pupillary margin of the iris. They are part of the uveitis manifestations. The other option might be to confuse them with Busacca nodules, which are on the trabecular meshwork, near the angle of the anterior chamber.

So the options might be A: Iris, B: Trabecular meshwork, C: Cornea, D: Lens. If the question is structured that way, the correct answer would be the iris. But the user didn't provide the options, so I need to be precise. Let me confirm the exact location. Koeppe nodules are indeed located on the iris, specifically at the pupillary margin. Busacca nodules are in the angle.

Therefore, the correct answer should be the iris. The core concept here is the classification of granulomatous uveitis and the associated nodules. The clinical pearl is to differentiate between Koeppe and Busacca nodules based on their location and associated conditions. The incorrect options might include other structures like the cornea, lens, or trabecular meshwork. Each of these is incorrect because they are not the site of Koeppe nodules. The explanation should clarify that Koeppe is iris, Busacca is angle, and others are unrelated. That's the key point.

**Core Concept**
Koeppe nodules are granulomatous lesions associated with anterior uveitis, specifically located on the iris. They are diagnostic features of granulomatous inflammation, often seen in conditions like sarcoidosis, tuberculosis, or syphilis.

**Why the Correct Answer is Right**
Koeppe nodules are small, elevated, yellow-white nodules found at the pupillary margin of the iris. They result from infiltration of epithelioid cells and lymphocytes into the iris stroma, forming a granulomatous reaction. Their presence helps distinguish granulomatous uveitis from non-granulomatous types, guiding targeted diagnostic workup (e.g., for systemic infections or sarcoidosis).

**Why Each Wrong Option is Incorrect**
**Option A:** Trabecular meshwork – This is where Busacca nodules (not Koeppe) are located.
**Option B:** Cornea – Koeppe nodules are intraocular, not corneal.
**Option C:** Lens – Lens involvement occurs in posterior uveitis, unrelated to Koeppe nodules

✓ Correct Answer: B. Pupillary border of Iris