## Core Concept
Visual acuity is a measure of the sharpness of vision, usually expressed as a fraction where the top number refers to the distance (in meters) at which a person with normal vision can read the same line on the Snellen chart that the person being tested can read at a distance of the bottom number. The classification of visual acuity is crucial for determining the severity of visual impairment.

## Why the Correct Answer is Right
A visual acuity of 6/60 indicates that the individual can read at 6 meters what a person with normal vision can read at 60 meters. According to the World Health Organization (WHO) classification, visual acuity worse than 6/18 but equal to or better than 3/60 is considered **moderate visual impairment**. Therefore, 6/60 falls into the category of **moderate visual impairment**, which corresponds to **Option C**.

## Why Each Wrong Option is Incorrect
* **Option A:** This option is incorrect because 6/60 does not represent **normal vision** or **mild visual impairment**; it indicates a more significant level of visual impairment.
* **Option B:** This option is incorrect because, although closer, 6/60 specifically indicates **moderate visual impairment**, not **mild visual impairment**.
* **Option D:** This option is incorrect because 6/60 does not classify as **severe visual impairment**, which would be a visual acuity worse than 3/60 but equal to or better than 1/60.

## Clinical Pearl / High-Yield Fact
A useful clinical pearl to remember is the classification of visual impairment by the WHO:
- **Normal vision:** 6/6 to 6/18
- **Mild visual impairment:** worse than 6/18 but equal to or better than 6/60
- **Moderate visual impairment:** worse than 6/60 but equal to or better than 3/60
- **Severe visual impairment:** worse than 3/60 but equal to or better than 1/60

## Correct Answer: C. Moderate visual impairment.