lundi 19 mai 2014

Understanding The Basics Of A Vision Tester

By Tracie Knight


Vision testing appliances are specially designed appliances that can gauge and test different eye attributes. Eye testing can be both mandatory and voluntary exercise. People who want to have eye screening can do it so at will. It is however mandatory in certain jobs that employees maintain a good eyes always. Such jobs include military, public health, public driver, and medicine. The use of a vision tester may become necessary during recruitment, after some period, or both.

The device comes in a variety of colors, shapes, and designs. There are many manufacturers of these devices worldwide resulting in many models and designs. Latest models include several useful features that make them easier and convenient to use. The complexity of devices varies from simple basic models to room-sized models that require a whole room for installation.

Latest models of sight testers can work under different conditions. Some of the major conditions include near, distance, nighttime, daytime, monocular, and binocular. The incorporated light emitting diodes serve as a source of light whenever there is need. Major physical components on the device include handle, base, controls, eyepiece, and body. Each part has its own purpose on the gadget. For instance, the base provides firm support when the device is resting on a bench.

The body of the tester works as the housing for all circuitry the device contains. The body is mostly made from plastic although other materials can also be used. The handle provides easy support when moving the gadget from one place to another. One hand should hold the handle and the other one the base when carrying. Storage should be done in well insulated materials away from direct sunlight, water or moisture.

Vision testing appliances can test numerous eye conditions including visual color perception, acuity, depth perception, peripheral view, lateral phorias, long and near sightedness. In short sighted individuals, eyes are incapable to see text from close range. The appliance locates letters at varying virtual lengths from individuals being analysed. The individual is needed to look in the eyepiece and state what they see.

Color testing mostly focuses on two major colors and their shades. As one views through the eyepiece, text is placed against different background, mainly red, green, or their shades. One is then required to read the text or say its color. The text may also come is different colors. Long distance test involves placing text against different backgrounds. The sharpness of the text or background should remain the same. If the text looks brighter or sharper against one background than the other, then distance vision is not right.

Peripheral sight is the ability of one to see things on the sides when their eye is focused in front. The testing device is able to shift the position of the text one is required to read to different angles of the eye. There are standards in place that guide all the tests that are tested.

The complexity and presence of additional features on a tester are the key determinants of its price. Simple makes cost not over a few dollars whilst sophisticated models can go as far as several thousand dollars. The wide collection of makes accommodates individuals with various financial abilities.




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