[Skip to Content]

Visual Electrophysiology

Visual electrophysiology encompasses a number of techniques for recording electrical signals from the eye, optic nerve and the brain in response to visual stimuli. Electrophysiological responses are altered in a variety of ways by disease processes affecting the retina, optic nerve and the higher visual pathways.

Visual electrophysiological tests are requested for a range of reasons including diagnosis or exclusion of a specific condition, location of a problem at a particular level of the visual system, provision of an approximate objective measure of visual acuity, assessment of the maturity of the visual system in a pre-literate child and monitoring of the progress of a known condition.

Ophthalmologists with an interest in visual electrophysiology usually also have responsibility for another sub-specialty service which uses electrophysiological tests frequently (eg medical retina, paediatric ophthalmology, ocular genetics).   Electrophysiological testing is usually conducted by clinical scientists (eg neurophysiologists, medical physicists or optometrists) and the role of the ophthalmologist is usually to report the tests and provide clinical input to the care of the patient.

Quality Standards

The College does not currently make any specific recommendations for items of supporting information that should be provided for appraisal in this field, but suggests the following topics for audit:

  • Perceptions by patients and carers of the care provided by the service
  • Perceptions by referring clinicians of the efficiency and effectiveness of the service
  • External audit of the calibration of equipment.

Electrophysiological responses can be affected greatly by factors such as stimulus parameters, electrode placement, suppression of sources of electrical interference, calibration of equipment, pupil diameter and the state of light or dark adaptation of the patient, so it is critical that these variables are controlled as much as possible.

The International Society for Clinical Electrophysiology of Vision (ISCEV) sets and regularly reviews standards for the recording of all the common electrophysiological tests and these should be the benchmark for all visual electrophysiology services.

 Significant Events

Significant events relating to the operation of the service such as misdiagnosis or delayed follow-up should be reported via local reporting mechanisms and discussed at appraisal.

Electrophysiological tests are non-invasive, but it is possible that a flicker stimulus could provoke photogenic epilepsy in a susceptible individual. Such an event, or a malfunction of equipment that caused harm to a patient should be reported via the appropriate channels.

Innovations

Advances in electrophysiological techniques and equipment in the last 20 years, alongside advances in retinal imaging technology and genetic testing has greatly aided the understanding of many disorders of the visual system.

Resources

  • British Society for Clinical Electrophysiology of Vision The British chapter of the International Society for Clinical Electrophysiology of Vision (BriSCEV) was formed in 2003. The members of the society include physicians, Healthcare Scientists and other professionals who have an active interest in clinical electrophysiology of vision.
  • International Society for Clinical Electrophysiology of Vision The objectives of the society are; to promote and extend the knowledge of clinical electrophysiology of vision, and to promote co-operation and communication among workers in the field of clinical and basic electrophysiology of vision.