Clinic equipment

Perimetry consists of the two words Peri (meaning around) and Metery (meaning measurement) and generally means measurement of one's visual field function. Visual field disorder caused by retinal diseases, optic nerve and intracranial visual pathway diseases can be diagnosed and followed up by the Perimetry method. It should be noted that this test depends on the individual's responses. There are different ways of performing Perimetry. In the Standard Static (constant) Perimetry a dim light is first reflected in a specific position, If not realized, the luminosity is increased without changing the light position until one realizes it. This is called the threshold of that place.

This is repeated at different points and then the optical sensitivity of different parts is compared together. In Kinetic Perimetry (moving), the object (with unchanged size and brightness) is moved peripherally to the center of vision on different axes so that one can it see in each axis. These points connect contour lines of the visual field to make an lsopter inside which the objects can be seen but can’t be seen outside. The larger the lsopter, the better the visual field is. The brighter the object and the larger the object size, the larger the lsopter for that object is. Another way is Tangent Screen testing. Tangent Screen is the simplest Perimetry device. This technique uses white pins on a black board shown against a black screen. This method examines 30 degrees of the central visual field. In Goldman Perimetry method, patient sits in front of a hollow white hemisphere and his visual field is then examined and illustrated in both static and kinetic ways by luminous spots with adjustable intensity and size. Also in computerized automated Perimetry the threshold sensitivity of each part of visual field (Static Perimetry) is precisely specified in numerical order. This device can display the patient’s Perimetry in the form of diagrams made of the connection of similar points (in terms of sensitivity) as well as keep the result of patient’s Perimetry in its memory.

Using this device, we will be able to measure eye pressure. High eye pressure can lead to a condition called glaucoma, which, if left untreated, can damage one's eyesight and eventually lead to blindness. So it’s recommended that everyone over 40 years old should get tested every 3 or 5 years to prevent glaucoma.