Full field ERG
VEP acuity estimates
Patients have access to the latest electrodiagnostic technology at Essendon retina. The clinic is equipped to offer comprehensive assessment of the visual pathway in accordance with international Standards and Guidelines (ISCEV). Essendon Retina electrodiagnostic service welcomes referrals from GPs, ophthalmologists, neurologists and optometrists. Tests are chosen and conducted in line with the patient presenting symptoms or according to the referring practitioner requests. Often our electrodiagnostic work-ups include additional measures of visual function eg assessment of colour perception, contrast sensitivity, dark adaptometry or perimetry. The service is complemented by a suite of advanced imaging techniques, particularly to assist in monitoring chronic or progressive eye diseases.
Electrodiagnostic testing is indicated for those patients who present with:
- unexplained low visual acuity
- difficulty adapting to ambient lighting
- acquired colour vision anomalies
Diagnosis & Monitoring
The electrodiagnostic service receives referrals for diagnosing and monitoring those with retinal disorders (eg dystrophies such as RP, X-linked retinoschisis) and retinal toxicities (eg Plaquenil)
Current protocols mean that dysfunction of the retinal neurons can be detected with excellent sensitivity, even before visible structural, vascular or pigmentary changes in the eye. An electrodiagnostic work-up will provide evidence of a neural explanation to vision loss this will not be apparent on fundoscopy.
Different types of electroretinogram (flash, pattern and multifocal; also electrooculogram, EOG) are used to examine the health of retinal neurons. Whereas the pattern ERG is a sensitive indicator of early glaucoma, the multifocal ERG is useful for localising macular dysfunction, toxicity or oedema. The visual evoked potential (VEP) measures the size and timing of responses passed through to the visual cortex, providing information about neurological disorders (eg optic neuritis, neurodegenerations, chiasmic lesions, albinism).
Even for patients who have conditions for which there is no treatment, understanding the extent and nature of their visual loss along with its rate of progression can assist practitioners to give appropriate and more personal advice.
We offer a packaged suite of tests for assisting with diagnosing and monitoring optic neuropathy or demyelination.
Visual fields (static or Goldmann, as indicated)
We offer a packaged suite of tests for assisting with diagnosing and monitoring retinal toxicity due to Plaquenil. Current international guidelines recommend baseline ophthalmic assessment before initiation of treatment and then screening after 5 years. Indications for more regular screening include: new visual symptoms, renal/hepatic disease and higher cumulative doses.
Visual fields (10-2 for macular function)
Fundus autofluorescence imaging
Preparing for your appointment
Electrodiagnostic testing involves measuring very small electrical potentials from the eye or brain. We use sensitive detectors that must make good contact with the skin and therefore ask you to refrain from using facial skin products, where possible.
It is very likely that drops will be used to dilate your pupils during your appointment. Some patients notice blurry or glary vision for a few hours after their pupils have been dilated. Please bring sunglasses and arrange for someone to assist you with transport.
If you are referred for electrodiagnostic testing, please be aware that you will likely require a long appointment. Depending on the number of tests required, you might be in attendance for up to 3 hours.
Accounts are payable on the day of your appointment. Medicare rebates are available for most tests, although there is an additional out-of-pocket expense. Please call 03 8370 6236 for further information.