**Core Concept**
Intraocular lens (IOL) implantation is a common procedure following cataract surgery. However, there are specific conditions where IOL implantation is contraindicated due to increased risk of complications, such as infection, retinal detachment, or chronic inflammation.

**Why the Correct Answer is Right**
In conditions where the eye is inflamed or has a high risk of infection, IOL implantation is contraindicated. This is because the presence of an IOL in an inflamed eye can increase the risk of endophthalmitis, a severe and potentially blinding infection of the eye. **Uveitis** is a condition characterized by inflammation of the uvea, the middle layer of the eye. It can be caused by various factors, including infection, trauma, or autoimmune disorders.

**Why Each Wrong Option is Incorrect**
* **Option A:** There is no specific contraindication to IOL implantation in patients with **glaucoma**. In fact, IOL implantation can sometimes be used to manage glaucoma by reducing intraocular pressure.
* **Option B:** **Diabetic retinopathy** is not a direct contraindication to IOL implantation. However, patients with severe diabetic retinopathy may require additional surgical techniques or precautions to manage the condition.
* **Option C:** **Age-related macular degeneration** is not a contraindication to IOL implantation. However, patients with advanced macular degeneration may require additional surgical techniques or precautions to manage the condition.

**Clinical Pearl / High-Yield Fact**
In cases of suspected or known uveitis, it is essential to postpone IOL implantation until the inflammation has resolved to minimize the risk of postoperative complications.

**Correct Answer: C. Uveitis**