What is Electroretinography?
An eye test that detects the function of the light detecting portion of the eye i.e. the retina is known as an electroretinography. It is also known as electroretinogram. The test reveals any subclinical retinopathy. (1)
The retina is composed of specialized cells known as rods and cones that detect light and ganglion cells that transmit images to the brain.
Electroretinography picks up signals from the photoreceptors and other cells i.e. the intermediaries between the ganglion cells and the photoreceptors. This test is done to detect:
- Retinitis pigmentosa, a genetic disease that leads to the loss of peripheral and night vision.
- Macular degeneration, which occurs due to the death of cells in the macula and leads to loss of vision.
- Retinoblastoma, cancer of the retina
- Retinal separation, detachment of the retina from the back of the eyeball
- Con rod dystrophy, loss of vision due to impaired con and rod cell
How is Electroretinography Test Performed?
The patient is asked to lie down or sit in a comfortable position. Eye drops are put in the eye to dilate them. An anesthetic eye drop is then put to make it numb.
A retractor is used to hold open the eye. This helps to carefully place a small electrode on each eye. Electrode either resembling a contact lens or a fine thread is placed in the eye. An additional electrode is placed in the forehead skin.
The patient is then asked to watch a flashlight. The test is conducted in normal light and then in a darkened room. The electrodes help in measuring the retina’s electrical response to light.
The responses recorded in the lightened room are from the cones in the retina and those in a darkened room are from the rod cells in the retina.
The information is then transferred to the monitor, where it is displayed and recorded.
What Does The Electroretinography Test Result Mean?
A normal result shows the wave patterns of a normal eye in response to each flash of light.
The abnormal results may indicate the following conditions:
- Giant cell arteritis
- Retinal detachment
- Arteriosclerosis damage to the retina
- Cone rod dystrophy
- Vitamin A deficiency
- Congenital night blindness
- Diabetic retinopathy
- Open-angle glaucoma
Risks Associated With Electroretinography Test
There are no major risks associated with electroretinography. Slight discomfort is felt when the electrodes are placed in the eye. It feels as if an eyelash has lodged in the eye.
After the test is completed, there is slight soreness felt in the eye.
Some people suffer from corneal abrasions after the test. If detected early it can be treated easily.
It is important to follow the aftercare instruction given by the doctor. If any type of discomfort continues, bring it to the notice of the doctor who has performed the procedure.
The eyes may feel a bit sensitive after the test. Therefore, avoid rubbing them, as it may lead to corneal damage.
In the case of retinal separation, trauma, or any disorder, you may need surgery. Any other retinal condition is treated with medications.