Visual Electro-Diagnostic Clinic

22 Sanders St

Upper Mt Gravatt

Patient Information- visual tESTS


Visual tests performed at the Clinic (VEP, ERG, EOG, PERG, AVEP, MFERG & COLOUR VISION) are elective tests that look at the way your visual system is working in order to help with the diagnosis of any visual problem and possibly to guide towards appropriate treatments.

The tests will take between one and four hours. You will have drops put into your eyes to dilate the pupils. Electrodes will then be placed on your head and face to monitor the working of different types of visual signals, usually checkerboard patterns or flashes of light and to record these responses. For part of the time you may be sitting in a very dark room. In some parts of the test very fine silver thread electrodes will be gently placed onto the surface of the eye. This won’t be felt because of the eye drops which have numbed the eye. Fibre Electrodes for ERG Skin Electrodes for Child ERG

Electrodes and screen for VEP

Complications with these tests are very rare, but it is possible to have a reaction to the eye drops, causing some redness, or sore eyes. Very rarely patients have been known to faint. Micropore (adhesive medical tape) can cause irritation to sensitive skin and very rarely, people react to the placement of the very light electrodes onto the eye. You should alert the clinic if you have known allergies or have had a reaction to electrodes before.

Because your eyes will be dilated, you will have temporary sensitivity to light after the tests and your vision may be “blurry”.

*It is necessary to organise a driver to pick you up as your vision will remain blurry for several hours after testing

*Please do not wear face creams or makeup on the day

*All current glasses should be brought with you

*Contact lenses should not be worn

*Sunglasses are advised for after testing as your eyes will be glare sensitive due to the dilation

*For infants: it is suggested that you bring along a bottle and some favourite toys to help calm them. 


Your eyes may feel irritated up to an hour after testing. If persistent problems occur, please phone the Clinic 07 34204899

or email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Dr Stark established a visual electrodiagnostic clinic in 1979. Initially this clinic formed part of the NSU but now for 7 years it has been functioning solely as an ophthalmic institute.

The VEDC (Visual Electro Diagnostic Clinic)  continues to provide a unique visual diagnostic service for all of Queensland and northern New South Wales. A series of tests are performed which permit the investigation of Visual disorders and enables suitable management of patients who have retinal or optic nerve disorders.  These tests are described in detail in the ensuing articles in the the associated menu. These tests ere non-invasive and provide information regarding the eye and visual function not otherwise available. They are an addendum to the normal eye investigation and examination.

These tests are performed at the clinic sited within the EyeTech Day Surgery complex in Upper Mt Gravatt.

An overview of the tests provided is given in 2 papers Visual Electrophysiology and Visual Electrophysiology 2012. The latter paper was first published this year the former paper was updated late 2011. Further papers provide detals of specific conditions.

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Toxic Retinopathy
















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Male DOB 14/02/1955

Left eye has been weaker than Right several years; no specific symptoms

General Health Good; no medications

Ophthalmic: Visual Acuity R6/4.8 Left 6/7.5

No afferent pupllary defect

Refractive media clear;

Fundi: healthy optic discs and maculae; cop/disc ratio 0.3OU

Visual fields:  Right Normal, Left global decreased sensitivity more marked inferiorly. (attached) 



Cone disorders

Disorders of Receptor Cells (B) Cones

1. Cone Dystrophy 2. Achromatopsia

Cone dystropy description