Tableau de snellen

The Snellen chart is primarily used to assess visual acuity, which is the clarity or sharpness of vision at a distance. It’s a standard tool used by eye doctors to determine if someone needs glasses or if their existing prescription needs adjustment. The chart displays a series of letters of decreasing size, and patients read the letters from a set distance (usually 20 feet) to determine their visual acuity.

Description

Here’s a more detailed explanation:
1. Measuring Visual Acuity:
The Snellen chart helps determine how well a person can see letters or symbols at a specific distance.
It’s a quick and easy method to assess both monocular (one eye) and binocular (both eyes) vision.
The chart’s geometric scale provides a numerical representation of visual acuity, with 20/20 vision being considered normal.

2. Identifying Vision Problems:
If someone can’t read the letters on a particular line of the Snellen chart, it indicates they have a reduced visual acuity at that distance.
This information helps eye doctors determine if corrective lenses (glasses or contacts) are needed or if the existing prescription needs to be updated.

3. Other Applications:
The Snellen chart can also be used to:
Monitor changes in vision over time.
Assist in the diagnosis of eye diseases or refractive errors.
Provide a baseline record of vision for medico-legal reasons.