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Perimetry is the systematic measurement of the field of visual function (the total area where objects can be seen in the peripheral vision while the eyes focused on the mid point). Two types of most commonly used a kinetic perimetry is perimeter and threshold perimetry automatically static.
Visual field test (perimetry) will detect a loss of peripheral vision and provide a map of the body that will help in diagnosing the cause of losses. Two types of most commonly used a kinetic perimetry is perimeter and threshold perimetry automatically static. The visual field is mapped to the lights of varying size and brightness.
To do the test, you sit down and look into the bowl shaped instrument called a perimeter. While You stare at the center of the bowl, the lights flash. You press a button whenever you see a flash. The computer keeps track of where every flash and if you press the button when the light flashed in the place.
People with open angle glaucoma may have a certain pattern of vision loss. Vision loss first occurred furthest from the center of the eye, usually on the side of the nose first. As the disease gets worse, the wider area of vision loss are visible on the test spirometry.
Perimetry test is a good test to find the loss of vision caused by glaucoma. Perimetry tests make detailed notes of your visual field. Basic information, descriptions or pictures can be compared with the test results in the future. Perimetry tests can be done quickly, but it may take more than 45 minutes when both eyes are tested.
Traditionally we tested visual function as visual acuity-the capacity to distinguish fine details of objects and the visual field of the space in which the object is seen at the same time during steady fixation of the gaze in one direction. Color vision testing, the sensitivity of contrast sensitivity, flicker, motion and pupillary response testing are some of the other methods for quantitating vision.
This visual sensitivity map, created by one of these methods, it is very important in diagnosing diseases of the visual system. Different patterns of visual loss found with diseases of the eye, central nervous system the optic nerve. A new device called a virtual perimetry is now available for visual field testing. This method automatically tests can help detect neurological damage from brain injuries or diseases such as glaucoma.
New devices perform this task by identifying blind spots in the visual field. The most significant difference this new device and testing method of conventional visual is that of virtual automated perimetry. The conventional way of visual field testing requires subjective responses from patients with pressing a button once there is flashing in a different part of the screen. When it comes to test subjects who are very young or old, conventional tests of visual defects. In contrast, Virtual perimetry can automatically detect and measure the eye responds to visual stimuli.
With automated perimetry in static thresholds, computer programs are selected. The most commonly used one test center 30 ° of the visual field that uses a grid of six degree spacing. Eye area that provides sharp, Central vision (macula) You usually use to read damaged later in the disease. This can lead to total blindness.
This is achieved by keeping the size and location of the target of constant and vary the brightness until the target most patients can look at each test location was found. Loss of peripheral vision is often the initial sign of glaucoma. Perimetry tests can help find certain patterns of loss of vision. This may mean there are certain types of eye diseases. It is very useful in finding the beginning of a change in vision caused by nerve damage from glaucoma.