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Kamis, 01 Mei 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 makes can work under various conditions. Among those conditions are nighttime, daytime, monocular, binocular, near, and distance. Light can be provided by the light emitting diodes, which are normally incorporated in the device. Major physical parts on most devices include controls, eyepieces, handles, bases, and bodies. Each component has its own work on the gadget. For example, bases provide firm support when carrying or using the device 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 is mostly concerned with two or three main colors and their shades. Text is placed against various backgrounds, mainly green, red, gray, or their shades. Individual under test is required to read it or state its color. Sometimes the text is presented in different colors. Test for long sightedness also involves placing letters against backgrounds of different colors. One should see the sharpness of the letters as same regardless of the background. Long sightedness occurs when one sees the brightness or sharpness to be changing with change in background.

Peripheral sight is concerned with the ability of someone seeing items on the sides while the eye is looking in front. The device shifts the position of texts one is supposed to see to different view angles. Various states have standards that regulate all tests administered to clients by service providers.

The price of the device varies depending on the level of complexity and features that come with it. The simple ones go for a few dollars while complex ones may cost thousands of dollars. The wide variety accommodates the varying financial capabilities of people.




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