**Core Concept**
Blepharitis acarica, also known as demodectic blepharitis, is a type of blepharitis caused by a parasitic mite infestation. This condition is characterized by the presence of Demodex mites on the eyelids, leading to inflammation and irritation.

**Why the Correct Answer is Right**
The Demodex mite is a small, eight-legged arachnid that inhabits the hair follicles and sebaceous glands of the eyelids. The mites feed on the oils produced by the meibomian glands, leading to an inflammatory response and blepharitis. The condition is more common in individuals with compromised immune systems or those who wear contact lenses.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because blepharitis caused by demodectic mites is not related to bacterial infections.
**Option B:** This option is incorrect because staphylococcal blepharitis is a different condition caused by bacterial infections, not parasitic infestations.
**Option C:** This option is incorrect because vernal keratoconjunctivitis is a seasonal allergic condition affecting the eyes, not a type of blepharitis.
**Option D:** This option is incorrect because seborrheic blepharitis is a type of blepharitis caused by seborrheic dermatitis, not parasitic infestations.

**Clinical Pearl / High-Yield Fact**
Demodex mites can be difficult to diagnose, but they can be identified using a skin scraping or biopsy. Treatment typically involves topical or oral antibiotics to control the infestation and reduce inflammation.

**Correct Answer: D. Seborrheic blepharitis**