Celeris User Manual
14770-A || ECN # 844 || ECN Date: 28 July 2017 Page 11 of 23
Full-Field Stimulator electrode
• Make sure that the eye has been wetted before placing the electrode.
• Be sure to make contact with the cornea – making contact solely through the wetting solution will
decrease amplitudes.
• Make sure to not put pressure on the eye – the contact should be just that, contact. Putting undue
pressure on the eye will increase intraocular pressure and consequently reduce blood flow to the retina,
resulting in decreased amplitudes.
Pattern Stimulator Electrode (Optional component)
• Ensure that the electrode is clean before use! See the cleaning section for details.
• Important: when the stimulator is placed correctly, you should be able to see a bit of the cornea
above the stimulator. If you are unable to visualize the cornea, you may be putting too much pressure
on the eye and may need to pull the stimulator back slightly.
• Despite relying on visual acuity, this is a dilated test! The stimulator imposes its own aperture on the
eye, so make sure that the animal is maximally dilated, and that the electrode is positioned so that it’s
pointing down the optical axis.
• Make sure that the eye is clear and without cataracts before starting the test! This test is dependent on
visual acuity and vision-compromising cataracts will adversely affect the response.
• Make sure that there are no whiskers stuck to the eye. This can interfere with the optics and affect the
response.
• If you are not getting a response – look in the stimulus viewing window directly above the stimulator
aperture to determine that the stimulus is running.
• Be careful with the amount of hypromellose/wetting solution used. Too much can make it difficult to
visualize the eye in the dark.
• While this is not technically a dark adapted protocol, we find we get the best mouse PERGs in the dark.
Dark adapted mice tested in the dark is best, but the dark adaptation need not be total.
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