látóélesség

Látóélesség, commonly referred to as visual acuity, is a measure of the eye's ability to discern fine details. It is typically assessed using a standardized chart, such as the Snellen chart, which presents a series of letters or symbols of decreasing size. The patient's ability to identify these characters at a specific distance determines their visual acuity.

Visual acuity is usually expressed as a fraction, such as 20/20. The numerator represents the distance in feet at which the patient can read a particular line on the chart, while the denominator indicates the distance at which a person with normal vision can read the same line. Therefore, 20/20 vision signifies that the individual can see at 20 feet what a person with normal vision can see at 20 feet. A score of 20/40 means the individual needs to be 20 feet away to see what a person with normal vision can see at 40 feet, indicating poorer acuity. Conversely, 20/15 suggests better-than-normal vision.

Factors influencing visual acuity include the clarity of the optical pathway (cornea, lens, vitreous humor), the health of the retina, and the function of the visual cortex in the brain. Refractive errors like myopia (nearsightedness), hyperopia (farsightedness), and astigmatism can reduce visual acuity. Other conditions, such as cataracts, macular degeneration, or optic nerve damage, also significantly impair the ability to see fine details. Regular eye examinations are crucial for monitoring visual acuity and detecting potential vision problems early.