Preparing for a visual field test

VISUAL FIELD TESTING IN GDAŃSK — INFORMATION ABOUT THE TEST:

A visual field test involves plotting the visual field on charts — the area you can see while keeping your eye still. Visual field testing is performed using a modern OCULUS device at Centralny Ośrodek Zdrowia ETER-MED (ETER-MED Central Health Centre) at ul. Żabi Kruk 10. The visual field is the set of points in space perceived at the same time as the fixation point, towards which the line of sight is directed. Comparing successive tests makes it possible to monitor how the visual field changes over time. Patients with glaucoma should have the test at least once every six months. The normal visual field of each eye extends approximately:

• Towards the temple: up to 85º-90º
• Towards the nose: up to 55º-60º
• Upwards: up to 45º-55º
• Downwards: up to 65º-70º

DESCRIPTION OF THE TEST:

Visual field testing requires a high level of attention and close cooperation from the patient, as the visual field is plotted based on their responses. You sit in front of the illuminated hemispherical bowl of a perimeter, with your head held still by resting your chin and forehead on special supports. One eye is covered. Throughout the test, you must look steadily at a point in the centre of the bowl, directly in front of the eye being tested. This is essential for the test to be performed correctly. A light target of a specific diameter and brightness appears elsewhere on the perimeter bowl. Your task is to report, without looking away from the central point, whether the target is visible, is fading or has disappeared completely. The examiner marks this information on a chart and, if necessary, repeats the test, changing the diameter, brightness and colour of the moving target. Joining the marked points with the same parameters produces lines known as isopters, which define the extent of the visual field. The test takes from a few to several dozen minutes.

PURPOSE OF THE TEST:

This test shows any areas of visual field loss on a chart, including their location and size, separately for each eye. These most commonly correspond to areas of the retina where light stimuli are not detected because of disease affecting the retina itself or a disruption of the pathways carrying stimuli to the visual centres in the brain. Computerised visual field testing is used to diagnose glaucoma, a range of pathological changes in the eye and damage to the visual pathways. Visual field testing is therefore important both for diagnosing damage to the visual system and for locating other abnormalities within the skull.

INDICATIONS FOR THE TEST

• Professional drivers, pilots and machine operators
• Nervous system disorders (especially those affecting the brain)
• Optic nerve disorders
• Glaucoma
• Retinal detachment
• Disorders of the retina and choroid.

PREPARATION AND CONTRAINDICATIONS FOR THE TEST

There are no special preparation requirements for the test. However, it requires a high level of attention and close cooperation from the patient, as the visual field is plotted based on their responses. For this reason, the test is not performed in young children, people with intellectual disabilities or older people who are disorientated. An important aspect is choosing the appropriate test method for the condition suspected in the patient. It is therefore advisable to have a referral from an ophthalmologist specifying the appropriate test method. If you do not have a referral, the person performing the test will choose an appropriate method after speaking with you. Near-vision glasses (reading glasses) are also helpful during the test for patients who use them.

HOW LONG WILL YOU WAIT FOR THE RESULT?

The visual field test result is provided as a written description with an accompanying chart on the day of the test. The result report is issued in Polish.

WHERE AND HOW CAN YOU HAVE THE TEST?

Visual field testing in Gdańsk is available at Centralny Ośrodek Zdrowia ETER-MED (ETER-MED Central Health Centre) at ul. Żabi Kruk 10