Eye tests diagnoses curable and incurable diseases present in the eye. An optometrist or ophthalmologist helps in monitoring vision, by performing various eye tests. Eye check-ups or eye testing at regular intervals in a periodic manner proves beneficial. As many eye problems l in the reveal no symptoms, routine and repetitive care is essential. Eye tests are helpful, in the remedy of many eye disorders, tumors and brain abnormalities. Clarity and accuracy of vision depends on the nerves and the assessment capacity of the brain.
Visual acuity or testing eye sight is a procedure that helps in detecting black symbols on a white base and is the measurement of vision. The distance by which all things are isolated by an angle of a single arc minute are differentiated as objects that are aloof is termed as ’20-20’ vision, which is 6-6 vision at the laymen level.
The efficiency of an individual to differentiate things on the basis of the frequency of light they give or reflect. The cone in the eye comprises of photoreceptors that produce color and is forwarded to the nervous system. There are three kinds of cones referred to as trichromatic color vision and it varies among individuals, based on the quantity and frequency. Majority of the mammals are dichromats, thereby possessing negligible or no color vision. The visible spectrum is at a range of 380 to 750 nm.
Color is viewed in the presence of an object, a source of light, and the eye. A blue ball absorbs all the visible light frequencies, apart from a frequency group termed blue. An analysis between various wavelengths is perceived by the human eye. Visual processing allows surface differentiation and color is an aspect created by the human brain. The eyes have to assess the objects around in a proper format and then react to them. Color is perceived in mammals by receptors that possess pigments that are sensitive.
The hand-eye coordination procedure is done to evaluate the adjustment capacity of the brain based on environmental changes. A test sheet is paste on a vertical surface like a wall at the eye-level in front of each individual. The person is made to stand at an arm’s length, so that the sheet can be easily reached. Each individual is entitled for three trials and three tests. There are three sets of trials and same number of tests that each candidate must perform, thereby doing the activity 9 times. The aim of the procedure is, in a minimum span of time, a line is drawn inside the borders on the broad lines from the start at the ‘BEGIN’ circle till the ‘END’ circle on the test sheet.
The most commonly seen eye testing product is the eye chart. They are of domiciliary type and wall mounted and motorized type with 4 sides. A standard eye distance chart is printed in black and involves other colors, such as, red and green lines. Color perception by individuals is assessed by this procedure.