**Core Concept**
The ability of certain bacteria to invade the intact corneal epithelium is a critical factor in the pathogenesis of corneal infections. **Neisseria** species are known for their invasive capabilities. The corneal epithelium serves as a barrier against infections, and its integrity is crucial for maintaining eye health.

**Why the Correct Answer is Right**
The correct answer is related to the specific bacteria that cannot invade intact corneal epithelium. **Neisseria gonorrhoeae** and some other bacteria can adhere to and invade the corneal epithelium, but others may require a breach in the epithelial layer to cause infection.

**Why Each Wrong Option is Incorrect**
**Option A:** Some bacteria can invade intact epithelial layers due to their virulence factors.
**Option B:** Certain species are known for their ability to invade epithelial cells.
**Option C:** This choice might be incorrect because it could represent a bacterium that indeed can invade the corneal epithelium.

**Clinical Pearl / High-Yield Fact**
It's crucial to remember that **Neisseria gonorrhoeae** can cause severe conjunctivitis and can invade the corneal epithelium, leading to corneal ulcers and potentially serious complications if not treated promptly.

**Correct Answer:** D. Pseudomonas aeruginosa