Chronic amoebic keratitis is seen in:
**Core Concept**
Chronic amoebic keratitis is a condition characterized by a persistent infection of the cornea by the amoeba Acanthamoeba, leading to inflammation and potential vision loss. This condition often occurs in individuals who wear contact lenses, particularly those who expose their lenses to contaminated water.
**Why the Correct Answer is Right**
The correct answer is associated with the use of contact lenses, particularly those that are not properly cleaned and disinfected. When contact lenses are exposed to contaminated water, the amoeba Acanthamoeba can adhere to the lens and subsequently infect the cornea. This can lead to chronic inflammation and scarring of the cornea, resulting in vision loss. The pathogenesis involves the amoeba penetrating the corneal epithelium and causing a granulomatous reaction.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not address the specific risk factor associated with chronic amoebic keratitis.
**Option B:** This option is incorrect because it is not a recognized risk factor for chronic amoebic keratitis.
**Option D:** This option is incorrect because while it is a risk factor for other types of eye infections, it is not specifically associated with chronic amoebic keratitis.
**Clinical Pearl / High-Yield Fact**
Chronic amoebic keratitis is often seen in contact lens wearers who expose their lenses to contaminated water, such as swimming in lakes or hot tubs.
**Correct Answer: C. Contact lens use, particularly with contaminated lenses.**