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- What is electroretinography (ERG)?
- How is an ERG done?
- What do the electrodes do?
- How are electroretinography readings made?
- Why is an ERG done?
- What diseases is my doctor looking for with an ERG?
- What is a multifocal ERG?
- What is a normal outcome for an ERG?
- What does an abnormal ERG mean?
- Does the ERG test hurt?
- What are the risks of an ERG test?
- How long does the ERG test take?
- How about after the ERG test?
- How much does an ERG test cost?
Does the ERG test hurt?
The test is painless. However, the electrode that rests on the eye may feel a little like an eyelash has lodged in the eye. This sensation may persist up to several hours following completion of the ERG.
What are the risks of an ERG test?
There are no risks specifically associated with an ERG. Some patients experience mild ocular discomfort during or after the procedure. Rarely, a corneal abrasion may occur, which is readily treated with early detection. If you believe you have irritation or a corneal abrasion following an ERG, you should call your eye doctor or the doctor who ordered your ERG.
How long does the ERG test take?
The ERG takes about an hour or less.
How about after the ERG test?
One should not rub the eyes for an hour after an ERG (or any test in which the cornea has been anesthetized), so as not to injure the cornea.
How much does an ERG test cost?
Generally speaking, an ERG will be billed by your doctor or your hospital back to your insurance company. The same vagaries that haunt the billing process for most complex cases can undoubtedly affect collections for ERG. Any claim can lead to some reimbursement rejections by insurance or difficulties for patients tasked with handling their own billing matters. The cost for an ERG performed on a Medicare patient is about $150. Medicaid reimbursement may be lower.
Medically reviewed by William Baer, MD; Board Certified Ophthalmology
National Institutes of Health