Contrast Sensitivity (CSF) Check

Contrast sensitivity is the black-and-white contrast (contrast) of the surface of the object required to determine the spatial frequency (week/degree) of the different size objects of the visual system. It is used to evaluate the resolving power of the visual system for objects of different sizes, so it is a kind of New visual function quantitative test. The subject is 3 meters away from the watch, wearing the best refractive correction mirror, first measuring the right eye, then measuring the left eye, the measurement order from Table 1 to Table 4, the visual target from large to small, until the subject can not Before correctly reading the two lines of the minimum line, try to encourage the subject to read the next line of small objects. The measurement results of each subject are recorded on the record sheet. Basic Information Specialist Category: Ophthalmic Examination Category: Other Inspections Applicable gender: whether men and women apply fasting: not fasting Tips: Keep a normal mindset. Normal value The shape of the vision system is determined by vision, which is usually measured at high contrast. The contrast (modulation) is determined by the brightness of the object versus the background brightness. Contrast = (object brightness - background brightness) / (object brightness + background brightness). Contrast sensitivity (CS) is defined as the reciprocal of the contrast threshold that the vision system can perceive. Contrast sensitivity = 1 / contrast threshold. If the contrast threshold is low, the contrast sensitivity is high, and the visual function is good. Clinical significance Abnormal results can lead to contrast-sensitive abnormalities in the early stages of glaucoma and optic nerve disease. Need to check the crowd for refractive errors. Precautions Taboo before inspection: avoid fatigue. Requirements for inspection: moderate light. Inspection process The subject is 3 meters away from the watch, wearing the best refractive correction mirror, first measuring the right eye, then measuring the left eye, the measurement order from Table 1 to Table 4, the visual target from large to small, until the subject can not Before correctly reading the two lines of the minimum line, try to encourage the subject to read the next line of small objects. The measurement results of each subject are recorded on the record sheet. Not suitable for the crowd Inappropriate crowd: people with ametropia.