Three different types of eye charts used for measuring visual acuity:
Eye charts are tools used by eye care professionals to measure visual acuity, which is the clarity or sharpness of vision. Here’s how they work:
Positioning: The patient is positioned at a specific distance from the chart, usually 20 feet (6 meters) for a standard Snellen chart. For smaller rooms, mirrors might be used to simulate this distance.
Reading the Chart: The patient covers one eye and reads aloud the smallest line of letters they can see clearly. This process is repeated for the other eye.
Scoring: Each line of the chart corresponds to a visual acuity score. For example, if you can read the line labeled “20/20,” it means you have normal visual acuity. If the smallest line you can read is labeled “20/40,” it means you see at 20 feet what a person with normal vision sees at 40 feet.