WHO definition of blindness is a visual acuity in the better eye equal to or less than:
**Core Concept**
The World Health Organization (WHO) defines blindness based on visual acuity, which is a measure of the sharpness of vision. This definition is crucial for epidemiological studies and healthcare planning. The **visual acuity** threshold is used to categorize individuals as blind or having low vision.
**Why the Correct Answer is Right**
The WHO definition of blindness is based on a visual acuity of 3/60 or less in the better eye. This threshold indicates a significant impairment of vision, affecting an individual's ability to perform daily tasks and interact with their environment. The **better eye** is considered to account for individuals who may have unilateral vision loss.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not match the WHO definition.
**Option B:** Incorrect as it is not the correct threshold for blindness.
**Option D:** Incorrect because the correct answer is a specific visual acuity threshold.
**Clinical Pearl / High-Yield Fact**
The WHO definition of blindness is important for healthcare providers to understand, as it affects the classification and management of patients with visual impairments. Remembering this definition can help in assessing the severity of visual loss and providing appropriate care.
**Correct Answer:** Correct Answer: C. 3/60.