How Do You Use a Vision Chart?

Using a vision chart, often a Snellen chart, primarily involves standing at a specific distance and reading letters to assess your eyesight.

Here's how it's typically done based on standard procedures:

Basic Steps for a Vision Test

1. Positioning: You stand 20 feet away from the vision chart.
2. Correction: You perform the test without your glasses or contacts unless specifically instructed otherwise.
3. Testing One Eye: You cover one eye with your hand or an occluder.
4. Reading the Chart: You read out the letters on the chart, starting from the top and going down. The goal is to identify the smallest line of letters you can see clearly.
5. Testing the Other Eye: You then cover the other eye and repeat the reading process from step 4.

It's worth noting that the exact setup can vary. In some offices, instead of standing 20 feet from the chart directly, you view the chart through a mirror. This setup is used when space is limited but still simulates the 20-foot distance.

The result of this test is typically recorded as a fraction (e.g., 20/20, 20/40), indicating how well you see at 20 feet compared to what a person with normal vision sees at that distance.