logMARskálával

The logMAR scale is a system used in optometry and ophthalmology to measure visual acuity. It is derived from the "M" notation, which represents the distance in meters at which a person can read a specific line of a standardized eye chart. The logMAR scale converts these distances into a logarithmic unit, making the data easier to analyze and compare.

The scale is designed so that a decrease of 0.1 on the logMAR scale corresponds to a doubling of visual acuity. For example, a logMAR value of 0.0 represents normal visual acuity (20/20 or 6/6). A logMAR value of 1.0 indicates a visual acuity of 20/200 (6/60), meaning the person can see at 20 feet what a person with normal vision can see at 200 feet. Conversely, a logMAR value of -0.3 would indicate better than normal vision, such as 20/10 (6/3).

This standardized system is widely used for clinical assessments, research studies, and the evaluation of visual impairment. Its logarithmic nature helps to represent small changes in visual acuity more effectively than linear scales. The logMAR chart, often referred to as the ETDRS chart (Early Treatment Diabetic Retinopathy Study chart), is specifically designed for use with this scale, featuring rows of letters with decreasing sizes at equal logarithmic intervals. The simplicity and standardization of the logMAR scale contribute to its reliability in quantifying and tracking vision.