How far should the patient stand from the Snellen eye chart during an eye assessment?

The correct distance for a patient to stand from the Snellen eye chart during an eye assessment is 20 feet. This specific distance is based on the standard design of the Snellen chart, which allows for optimal visualization and accurate assessment of visual acuity. At 20 feet, the chart presents letters that are scaled appropriately for determining whether the patient can read them at standard sizes compared to what a person with normal vision can see from that distance.

The Snellen chart is calibrated so that each line of letters represents a specific visual acuity. When patients are positioned at 20 feet, the test helps to ensure that the results reflect the true ability of the patient's vision in comparison to the normative data. This standardized distance also minimizes potential errors related to perceived size and distance, thus ensuring consistency and reliability in the assessment across different individuals.