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Visual acuity ( VA) commonly refers to the clarity of vision, but technically rates an animal 's ability to recognize small details with precision. Visual acuity depends on optical and neural factors. Optical factors of the eye influence the sharpness of an image on its retina.
Infant vision concerns the development of visual ability in human infants from birth through the first years of life. The aspects of human vision which develop following birth include visual acuity, tracking, color perception, depth perception, and object recognition . Unlike many other sensory systems, the human visual system – components ...
Lea test. logMAR chart. An eye chart is a chart used to measure visual acuity comprising lines of optotypes in ranges of sizes. Optotypes are the letters or symbols shown on an eye chart. [1] Eye charts are often used by health care professionals, such as optometrists, physicians and nurses, to screen persons for vision impairment.
Visual acuity drastically decreasing (two levels or more), e.g.: 20/20 to 20/80 Blurred vision: Those with nonexudative (dry) macular degeneration may be asymptomatic or notice a gradual loss of central vision, whereas those with exudative (wet) macular degeneration often notice a rapid onset of vision loss (often caused by leakage and bleeding ...
Central serous chorioretinopathy ( CSC or CSCR ), also known as central serous retinopathy ( CSR ), is an eye disease that causes visual impairment, often temporary, usually in one eye. [1] [2] When the disorder is active it is characterized by leakage of fluid under the retina that has a propensity to accumulate under the central macula.
The World Health Organization (WHO) recommends at least 80% of eyes should have a presenting visual acuity of 6/6 to 6/18 (20/20 to 20/60) after surgery, which is considered a good enough visual outcome; the percentage is expected to reach at least 90% with best correction. Acuity of between 6/18 and 6/60 (20/60 to 20/200) is regarded as ...
Eccentricity effect. The eccentricity effect is a visual phenomenon that affects visual search. As retinal eccentricity increases (i.e. the light of the image enters the eye at a larger angle and approaches peripheral vision), the observer is slower and less accurate to detect an item they are searching for. [1]
A second peg, below it, can be moved back and forth until it is just detectably nearer than the fixed one. Stereoacuity is defined as the minimum angle detectable, calculated as the difference between the angles subtended by both positions, A and B. Stereoacuity is possible due to binocular disparity, i.e., the difference in their binocular ...