Látóélességmérés

Látóélességmérés, commonly translated as visual acuity testing, is a fundamental procedure in ophthalmology and optometry used to determine the clarity of an individual's vision. It quantifies how well a person can see fine details at a distance. The most widely recognized method involves using a Snellen chart, a standardized arrangement of letters or symbols that decrease in size from top to bottom.

During a typical visual acuity test, the patient is asked to read the smallest line of letters they can discern from a specific distance, usually 20 feet (or 6 meters). The results are typically expressed as a fraction, such as 20/20. The top number represents the distance at which the test is conducted, and the bottom number indicates the distance at which a person with normal vision would be able to read that same line. Therefore, 20/20 vision means the individual can see at 20 feet what a person with normal vision can see at 20 feet. A result like 20/40 indicates that the person can only see at 20 feet what a person with normal vision can see at 40 feet, suggesting poorer visual acuity.

Variations of visual acuity testing exist for different age groups and abilities. For young children or those unable to read, charts with pictures or symbols (like the Lea Symbols chart or the Tumbling E chart) are employed. Near visual acuity is also assessed, typically at a reading distance of 14-16 inches, using charts like the Jaeger chart. Látóélességmérés is crucial for diagnosing refractive errors such as myopia, hyperopia, and astigmatism, as well as for monitoring the progression of eye diseases and evaluating the effectiveness of corrective lenses or treatments.