During a Snellen eye exam, how far should the patient be from the examiner?

Testing at 10 feet does not provide the standard conditions needed for a Snellen eye exam. The distance is too short, which can lead to inaccurate assessment of visual acuity since the chart is calibrated for 20 feet. This shorter distance does not reflect typical visual conditions.

While being farther than the recommended distance might seem advantageous, testing at 25 feet can lead to unnecessary strain on the eyes and may not provide a consistent measurement. The Snellen chart is designed to be used at 20 feet, and altering this distance can result in discrepancies in visual acuity results.

Testing at 15 feet is also not appropriate, as it deviates from the standard practice of 20 feet. While it is closer to the recommended distance than 10 feet, it still does not align with the established protocol for the Snellen eye exam, which could compromise the accuracy of the results.