Näöntarkkuustesti

Näöntarkkuustesti, often referred to as a visual acuity test, is a standardized examination used to measure how clearly an individual can see. It is a fundamental component of eye examinations and is crucial for diagnosing a wide range of vision problems. The most common method involves using a Snellen chart, which displays a series of letters or symbols of decreasing size. The patient is asked to read the smallest line they can discern from a specific distance, typically 20 feet (6 meters).

The results of a näöntarkkuustesti are expressed as a fraction, such as 20/20. The top number represents the distance at which the test is performed, and the bottom number indicates the distance at which a person with normal vision could read the same line. Therefore, 20/20 vision is considered standard or normal visual acuity. A result like 20/40 means the individual can see at 20 feet what a person with normal vision can see at 40 feet, indicating poorer acuity. Conversely, 20/15 suggests better-than-average vision.

Näöntarkkuustesti can be performed with or without corrective lenses, such as glasses or contact lenses, to determine the best possible vision. Variations of the test exist for individuals who cannot read letters, such as young children or those with certain disabilities. These may involve identifying pictures or E-shapes (tumbling E test). This simple yet effective test helps eye care professionals assess visual function and guide appropriate treatment or management strategies.