näköterävyystesti

Näköterävyystesti, often referred to as a vision test or visual acuity test, is a common examination used to measure how clearly a person can see. It is a fundamental part of a comprehensive eye examination and plays a crucial role in detecting vision problems and monitoring eye health. The most widely recognized type of näköterävyystesti uses a standardized chart, such as the Snellen chart, which displays rows of letters, numbers, 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 näköterävyystesti are typically expressed as a fraction. The top number represents the distance at which the test is performed (e.g., 20 feet), and the bottom number indicates the distance at which a person with normal vision could read the same line. For example, a result of 20/20 vision means the individual can see at 20 feet what a person with normal vision can see at 20 feet. A result of 20/40 means the individual sees at 20 feet what a person with normal vision can see at 40 feet, indicating poorer vision. Conversely, 20/10 would indicate better than average vision.

Näköterävyystestit are essential for diagnosing refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. They can also help detect other eye conditions like amblyopia (lazy eye), cataracts, and macular degeneration. Regular näköterävyystestit are recommended for people of all ages, from young children to seniors, to ensure optimal vision and identify potential issues early.