New: electrophysiology

Electrophysiological examinations serve to assess the functioning of the retina, optic nerves and visual system. They supply valuable data when making a diagnosis and controlling the treatment of many ophthalmological and general diseases which produce symptoms in the eyes.

We differentiate three basic types of electrophysiological examinations:

• electroretinographic (ERG) and electro-oculographic (EOG) examinations enabling information to be obtained about the functioning of individual layers of the retina
• visual evoked potential test (VEP) enabling an assessment of the functioning of the visual system from the macule through the optic nerve, the visual system to the visual cortex in the brain

The examination is painless. A monitor displays the appropriate pattern or flashes of light are sent to stimulate the eyes. By applying special electrodes to the patient’s scalp or eyeballs, the signal from the eyes is transmitted to an analyser and displayed on the monitor. In the case of ERG and EOG tests, this signal comes from individual layers of the retina, allowing us to detect and recognise which diseases affect even individual cells. The visual evoked potential test is a record of the electrical activity of the brain, and more specifically the visual cortex – the part of the brain responsible for receiving visual stimuli. In layman’s terms, the results of the examination informs us whether the visual route from the eye to the brain is working properly, and whether the brain is receiving the visual signal properly from the eye.

Basic indications for electrophysiological examinations are:

• sudden blindness or loss of visual acuity without any visible changes in the eyeball, disturbances in colour, twilight or night vision.
• changes in the field of vision (including those of indeterminate causes, in patients with suspected glaucomic damage, with general diseases such as high arterial pressure, cardiac ischaemia, generalised arteriosclerosis)
• assessment of neurological conditions (multiple sclerosis – diagnosing attacks and monitoring the course of the disease, brain circulatory disorders – ischaemic changes, aneurysms, neoplasts of the eye socket or brain, toxic damage to the optic nerve or visual centres, post-traumatic states) suspicion of hereditary retinal diseases, even at the stage where there are no visible changes in the basic ophthalmological examination. An assessment of the advancement of retinal damage in patients with visible changes to the eyeground and/or previously diagnosed dystrophy, or retinal degeneration and monitoring the progress of the disease (assessment of the chances of retaining sight during the illness, whether dystrophy genes are carried, examining children from families genetically predisposed – this enables early detection of the disease and appropriate direction of the child’s schooling and professional career)
• assessment of the condition of the visual organ before a planned operation to remove cataracts or a vitrectomy in patients with non-transparent optic centres in order to forecast the improvement in visual acuity
• assessment of the activity of the visual organ in a post-traumatic, post-operative, non-operative state (e.g. meningioma of the optic nerve), in chronic illnesses or those requiring long-term therapy with drugs which are potentially toxic for the visual organ.
• detection of diseases in the pre-clinical stages (e.g. damage to the optic nerve as a result of thyroid ophthalmopathy when visual acuity is still good), in order to start treatment early enough to retain sight
• assessment of the degree of sight loss and forecast of any improvement in visual acuity
• determining visual acuity and diagnosing patients who are uncooperative due to their age, arteriosclerosis, mental disorders, mental retardation, unwillingness to cooperate in the examination and more time has to be allocated to the examination, it may be necessary to dilate the pupils (it is worth bringing sunglasses). Because of this, vision may be weaker immediately after the examination (ERG). It is best to bring along your collected ophthalmological documentation, especially field of vision test, OCT optical coherent tomography), fluoroscein angiography and information about visual acuity. You will receive detailed information regarding preparation for the examination while registering for it.