Perimetry is one of the basic eye examinations, the purpose of which is to check if there are any defects in the field of view. Visual field testing is quick and painless and helps detect many eye diseases. This research is used, inter alia, in the diagnosis of glaucoma. What are the indications for perimetry? What is this examination about? How to interpret its results?

Perimetrytoexamination of the field of view , i.e. the space that we see without moving the eyeball. Its purpose is to detect any defects in the field of view. If the field of vision is correct, we can be sure that the retina perceives visual sensations throughout its entire area, that the optic nerve conducts the image correctly, and that the occipital lobes of the cerebral cortex are functioning properly.

There are two types of perimetry - kinetic and static. It is complemented bycampimetry.

Perimetry (visual field examination) - indications

The most common test is to diagnose or monitor glaucoma. It is helpful in the assessment of diseases of the optic nerve, retinal diseases (detachment, age-related macular degeneration), neurological diseases (intracranial tumors), as well as in poor visual acuity, in arterial hypertension and in the diagnosis of headaches of unknown origin.

People who cannot see something when looking ahead or cannot see something from the side of the field of view should come to the examination and must turn their head to see something.

This study is not recommended for children, people with intellectual disabilities and the elderly with disorientation because it requires concentration and cooperation with a doctor.

Perimetry (visual field examination) - how to prepare for the examination?

The examination does not require any special preparations. It is only advisable that the patient be calm and rested so that he can focus and cooperate with the ophthalmologist. It is also worth taking reading glasses with you.

Properly conducted examination should be preceded by a visual acuity check. The field of view examination is performed from a distance of about 30 centimeters, which is why, for example, a farsighted person must put on glasses, and a nearsighted person usually does not.

Perimetry (visual field examination) - what is it?

The patient sits down next to an apparatus calledpolometer. He looks at the screen with one eye (left and right) and signals with the use of a button or in words the moment of the appearance of a light point in his field of view. This creates a visual field map for each eye. There are points on it that the patient saw and those to which the patient did not react, suggesting a defect in the field of vision. In glaucoma, the defect first appears in the field of vision around the nose and moves to the center as the disease progresses. Temporal vision is the longest.

There are two methods of assessing the field of view. In the kinetic method, the point moves during the test, and in the static method - it appears and disappears. In the static method, the signal strength changes, some light stimuli seem very strong, others on the verge of perceptibility. Patient is not sure if he saw the flash or not.

Tested takes 10-15 minutes. The patient must be focused, looking at one point in order not to overlook the emerging light.

Perimetry (visual field examination) - results

The test result is presented in a graphic form - in the form of graphic maps with indicated losses and the degree of their severity. The test must be repeated. Only the second or third is believed to be reliable because the patient has already learned how to properly respond to the perceived light signals.

Perimetry (visual field examination) - complications

The field of vision examination is a non-invasive and painless examination. The eye is not touched, so it cannot be irritated or damaged. Therefore, after the visual field examination, the patient should not feel any discomfort. However, it requires concentration and concentration and is tiring for some patients.

Worth knowing

Do yourself a test

In order not to overlook defects in the field of vision, it is worth doing a field of vision test yourself from time to time. Before performing the test, remove the glasses. 1. Cover your left eye with your hand. Take a pencil in your right hand, hold it in front of you and stare at one point. Keeping your eyes on, move your hand in an arc to the right. 2. Stop where you can no longer see the pencil. If the field of view is correct, the arm should make a right angle arc - 90º. 3. Do the test again but keep going right. The angle should be slightly smaller (approx. 60º) as the nose restricts the field of view of the right eye. 4. Examine your left eye in a similar way, i.e. cover your right eye with your right hand and hold a pencil with your left hand. If you haven't achieved the required degree values, see an ophthalmologist for a visual field examination.

The text uses fragments of the articleAnna Jarosz from the monthly "Zdrowie".

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