From the Guidelines
The Snellen chart is the recommended tool for screening for impaired visual acuity in older adults, as it readily identifies impaired visual acuity and refractive errors are correctable 1. The Snellen chart is a standardized eye test used to measure visual acuity, consisting of rows of letters that decrease in size from top to bottom, with the standard viewing distance being 20 feet (6 meters). Some key points to consider when using the Snellen chart include:
- The test is used to measure visual acuity, with the results expressed as a fraction like 20/20, which is considered normal vision 1.
- The top number represents the distance from the chart (20 feet), while the bottom number indicates the distance at which someone with normal vision could read that line.
- For example, 20/40 vision means you must be 20 feet away to see what someone with normal vision can see at 40 feet.
- The larger the bottom number, the worse your visual acuity.
- During an eye exam, each eye is tested separately, and corrective lenses may be used to determine your best-corrected vision 1. Key benefits of using the Snellen chart include:
- It helps eye care professionals determine if you need glasses or contact lenses.
- It serves as a baseline for monitoring vision changes over time.
- It is a simple and effective way to identify impaired visual acuity, which is consistently associated with decreased functional capacity and quality of life in older persons 1.
From the Research
Snellen Chart Vision
- The Snellen chart is a tool used to measure visual acuity, but there is no direct mention of it in the provided studies 2, 3, 4, 5, 6.
- However, the studies discuss various aspects of age-related macular degeneration (AMD) and its impact on vision, which can be related to visual acuity measurements.
- Visual acuity is mentioned in study 3 as a factor in measuring vision-related activity limitation and preference-based status in patients with glaucoma and AMD.
- The studies focus on the diagnosis, treatment, and management of AMD, as well as its pathophysiology and future perspectives 2, 4, 5, 6.
- None of the studies provide information on the Snellen chart specifically, but they do discuss the importance of visual acuity and its measurement in the context of AMD and other eye diseases.