At Rapidus Ophthalmology, intraocular pressure is measured using a non-contact tonometer. During this completely painless examination, the eyes are not touched by the instrument, so no anaesthetic is needed.
Measurement of the critical fusion frequency
The CFF test, which checks the conduction of the optic nerve, can detect several problems. One of these may be optic nerve damage, which in most cases can be glaucoma.
But what exactly does this term mean?
CFF stands for Critical Fusion Frequency, which can be used to easily detect if the optic nerve area has become damaged. It defines a vibration number that indicates the degree of fusion with significant change, the essence of which will become clearer from the description of the test procedure.
Let us see how the CFF test is performed!
The CFF test takes only a few minutes and does not cause any discomfort. All the patient has to do is look at a flickering greenish-yellow spot of light about 30 centimetres away. If he or she perceives that this light is no longer flashing but glowing in a continuous beam, he or she should report it. You should then signal again when you see the light flicker again.
This process must be carried out separately for each eye in each direction. Since the lights flashing faster and faster are after a while no longer separated by the visual system of the eye, but fused together and seen as one, they can be perceived as continuous even when they are vibrating. It is just that it does not matter at which values this happens.
When might I need a CFF test?
The test can provide accurate information on the conduction velocity of the optic nerve, which, in addition to the aforementioned eye disease glaucoma, can be an important starting point for the investigation of various neurological diseases, including multiple sclerosis, but also diabetes. Thus, the data measured by the CFF device can be used as a screening test for visual pathology and for accurate diagnosis. On the other hand, it may also be useful to use this test from time to time to monitor the progression of existing problems and their possible improvement.