What is the primary method for assessing a patient's visual acuity?

The primary method for assessing a patient's visual acuity is to obtain a Snellen chart. This chart consists of letters of varying sizes that are designed to measure how well a person can see at different distances. The patient typically stands a specific distance away from the chart, usually 20 feet, and reads the smallest line of text they can clearly distinguish.

This standardized approach provides a reliable measure of visual acuity, which is crucial for diagnosing vision problems and determining the appropriate treatment. Additionally, the results from the Snellen chart test can be quantified, allowing for consistent documentation of a patient’s visual capabilities over time.

In contrast, other methods such as shining a penlight or requesting the patient to follow a finger do not provide a definitive measurement of visual acuity. Focusing on a distant object can help assess a patient's ability to see clearly, but without the structured measurement system that the Snellen chart provides, it is not considered the primary method for assessing visual acuity.