Electrophysiologic Testing Index

1. Electrophysiologic Testing Index 1) How to observe disorders of the visual system 7) Who needs an electro- diagnostic service 2) Objective measurement electrophysiologic service 8) Health monitoring and retinotoxic medication 3) Differences between structural and objective data 9) Standard examination: ERG / PERG / VEP / EOG 4) Early detection of diseases and carrier status 10) ISCEV Standards and ISCEV membership 5) Electrophysiologic services for children 11) How to do and strategy 6) How to examine infants

2. 1) How to observe disorders of the visual system The perimeter is one standard unit to check the visual field . Disorders will be detected with cooperative patients. Slitlamp, fundus foto, OCT, hyperfluorescence and ultrasound pictures are effective parts of the cross diagnosis. Phenotypic similarities and structural defects could be seen.

3. 2) Objective measurement Fundus, OCT or hyperfluorescence images are a very important tool for the diagnosis of the retina. Nevertheless there are frequently patients with normal images and abnormal electric recordings. Electrophysiologic services is the only objective measurement to see if there are normal or abnormal functions of the retina, optic nerve and visual pathway. To see the function of a car, you never will trust in a picture. You’ll start with starting the engine. And that is what we are doing with the rods and cones and then we will see if they are working or not.

4. 3) Differences between structural and objective data One patient is not like the other; some will show the phenotypical symptoms, some won’t. The fundus picture is a poor prognostic indicator for the different types of RP. Electro services is the first choice to separate the different types of macular dystrophies. AZOOR patients show in general a normal fundus, but symptoms are positive. Only the electro services will help to get the diagnosis (delayed 30Hz flicker and reduced EOG).

5. 4) Early detection of diseases and carrier status The earliest possible detection of the carrier status for genetic counseling is electro services. The electro diagnosis could help to answer the question: "If I have a baby, will it get blind?" Cases of early macular lesions will show reduced PERG even if the fundus is still normal. PERG will also help to give a prognosis eg. for the varieties of M. Stargard: from a fairly stable maculopathy to a progressive cone-rod dystrophy.

6. 5) Electrophysiologic services for children Generally the question is very different from adults. Does the baby see? Are there rods and cones? Functionality of the visual pathway? Ocular albinism? Electrophysiologic testing should be considered in cases of high ametropia in childhood to rule out associated retinal pathology. It is always a challenge to get this information. Infants can’t and should not be treated like adults!

7. 6) How to examine infants? Fast! The trick is to go in, get the data and then get the child out again as soon as possible before it gets upset. It is possible to use "AMBU" glue skin electrodes instead of standard cornea electrodes. The big advantage is to win few minutes before the little patients will get upset, the price is 20% of the amplitude level. It will be a screening and the variation will be higher. Nevertheless you will get an answer to the main questions: Does the baby see? Are there rods and cones?

8. 7) Who needs an electrodiagnostic service • Symptoms of neurological or ophthalmologic disease • Unexplained visual loss • Paediatric neurophthalmic practice • Monitoring health • Receiving retinotoxic medication • Detection of the disease • Providing quantitative assessment of the progress • of an eye disease • Assessment of retinal and optic nerve function • following trauma • Research

9. 8) Health monitoring and receiving retinotoxic medication Electroretinography is also of value in monitoring disease progression. The most frequently reported ERG abnormalities in patients with diabetic retinopathy include a reduction in b-wave and/or absence of OPs. Drugs with retinal toxicity: e.g. administering chloroquene for prophylaxis of malarial fever and rheumatoid arthritis should be monitored. Chlorpromazine, Thioridazine, Indomethacin, Quinine, Methanol, Gentamicin, Ethyl-m-Aminobenzoic Acid, Cisplatin, Glycine, Canthaxanthin, Vigabatin, Deferoxamine, and Sildenafil are also well known as agents with direct negative effects to the retina.

10. 9) Standard examination: ERG / PERG / VEP / EOG You will find in the Internet: A "Guide To Procedures" of the standard examination: http://www.iscev.org/standards/index.html The handling will be trained at special events, meetings and courses, e.g.: http://www.iscev.org/events.html http://www.briscev.org.uk/ How to do it with the Tomey EP-1000 you will get here... Schmidt@tomey .de

11. 10) ISCEV Standards and ISCEV membership Our best recommendations for the EP-1000 user: Get an ISCEV membership! Being part of the community comes along with a lot of advantages…. Share, learn and get together: knowledge and information interactions at the annual International Symposium of ISCEV is the highlight of the year. Clinical trainings in national ISCEV courses; knowledge exchange at the virtual meeting point in the Worldwide Web. And last but not least the official publication of the ISCEV: “Documenta Ophthalmologica”. The purpose of the journal is to promote the understanding and application of the Clinical Electrophysiology of Vision. (Clinical cases, oral sessions, poster sessions, original research articles and paper)

12. 11) How to do and strategy Standard VEP abnormal VEP normal VEP Pattern ERG mf ERG screening 19 Hex with DTL Low details normal PERG abnormal PERG normal P 50 abnormal P95 abnormal P 50 Optic Nerv dysfunction Standard ERG normal ERG abnormal ERG Macular dysfunction Retinal dysfunction