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The "LEA Numbers Test" was the second of the LEA tests that was developed and can be used to test the visual acuity of older children and even adults. This test has a layout similar to a typical Snellen chart, with lines of numbers decreasing in size towards the bottom of the page. Like the optotypes of the LEA Symbols Test, these numbers are ...
The test consists of 10 plates, containing a central colored dot surrounded by four peripheral dots of different colors. The subject is asked to choose the dot closest to the central hue. Among the four peripheral dots, three peripheral colors are designed in such a way that, it makes confusion with the central color in protan , deutan and ...
On photographs taken using a flash, instead of the familiar red-eye effect, leukocoria can cause a bright white reflection in an affected eye. Leukocoria may appear also in low indirect light, similar to eyeshine. Leukocoria can be detected by a routine eye exam (see Ophthalmoscopy). For screening purposes, the red reflex test is used.
An example of the Landolt C eye chart (also known as the Japanese eye chart.). Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision, while the ETDRS chart is designed for use at 4 meters. [16]
Another test, including Visual acuity (EVTS/OptimEyes), uses targets which change in size, contrast, and viewing time. This test was developed by Daniel M. Laby with colleagues and uses item response theory to calculate a vision performance score (core score). This specific test of visual function has been shown to correlate to professional ...
An Ishihara test image as seen by subjects with normal color vision and by those with a variety of color deficiencies. A pseudoisochromatic plate (from Greek pseudo, meaning "false", iso, meaning "same" and chromo, meaning "color"), often abbreviated as PIP, is a style of standard exemplified by the Ishihara test, generally used for screening of color vision defects.
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Nine color pairs are administered during the test, beginning with a red/green combination, to allow the patient to see these two colors prior to seeing a white light, which decreases testing errors. The examinee is shown the target for only two seconds, as color-deficient patients can sometimes correctly identify the colors with prolonged exposure.