A visual contrast test is one that is used to measure the visual acuity during an eye exam. The test utilizes a special chart that is designed to test how well the eye functions in different types of lighting. The test also measures your ability to distinguish objects from backgrounds that are similarly colored or similarly shaded.
There are several different types of visual contrast tests. However, each of these utilizes only one basic principle. The high contrast eye chart that is used in such a test consists of black colored letters that are displayed against white backgrounds, which are well lit.
Even people who have perfect vision may suffer from poor contrast sensitivity and those who do not have perfect vision may not necessarily suffer from poor visual contrast. People who do suffer from poor contrast may face serious challenges in identifying certain images and objects in abnormal weather or lighting conditions.
If you suffer from visual contrast problems, you may find it difficult to distinguish the boundaries in the objects that are juxtaposed against similarly colored or shaded backdrops. The crispness in vision is lost for those who suffer from low contrast sensitivity. However, this does not mean that they see blurred images. It simply means that the distinction of the boundaries of images is not very clear to the person.
Contrast vision is extremely important and therefore, is rightly known as ‘functional vision’. If, for some reason, you have low contrast sensitivity, you may have trouble driving at night and may even not be able to discern the pedestrians walking along the streets that are not very well lit. Apart from that, you may require some extra light in order to read and your eyes may tire very soon after reading or watching television for a short while.
Low contrast sensitivity is most often the symptoms of eye conditions that may not as yet have manifested themselves. Some of these problems include glaucoma, cataracts, and even diabetic retinopathy. If you have recently had a laser vision surgery procedure done, you may experience low contrast sensitivity as a side effect.
The charts used for this test can only assess your ability to view objects in terms of both contrast and size. However, in real life situations, the circumstances may be different and therefore, the test is not considered very accurate, and has some elemental flaws due to its inherent principles.