Visually Evoked Response: Educate Yourself Before Getting Tested

24 Mar 2022

Visually Evoked Response: Educate Yourself Before Getting Tested

An evoked potential induced by visual stimulation, such as an oscillating checkered pattern on a pc screen, is known as a visual evoked potential. Electrodes on the back of your head capture your responses, which are displayed as a readout on an electroencephalogram (EEG). The frontal cortex, the part of the brain that receives and interprets visual data, is frequently the source of these responses.

VEP Test Near Me:When does the VEP come into play?

When you have vision changes that could be caused by abnormalities along the routes of particular nerves, your doctor may prescribe that you get a VEP test. 

  1. Loss of vision (painful or non-painful); 
  2. Double vision;
  3. Blurred vision;
  4. Flashing lights; 
  5. Colour vision changes; or 
  6. Weakness of the eyes, limbs, or legs is one of the symptoms that can occur.

These changes are frequently too subtle or difficult to detect during a clinical examination in a doctor's office. The test is beneficial for identifying optic nerve disorders in general. This nerve helps us see by transferring impulses, so having it tested allows your physician to see how your optic system reacts to light. The test can also be used to examine the vision of adults and children that are unable to understand eye charts.

What does the VEP look out for?

The VEP measures how long a visual input takes to transit from the retina to the occipital cortex. It can help the doctor determine whether or not the neural pathways are abnormal. The insulating layer surrounding nerve cells in the brain and spinal cord (called the myelin sheath) can be compromised in multiple sclerosis. This indicates that electrical signals from the eyes take longer to reach the brain, resulting in an aberrant VEP. A good VEP can be pretty sensitive in excluding an optic nerve injury in the anterior region of the brain along with its courses.

How to Study for a VEP Exam

  1. Information on how to study for the test will be supplied to you. This will be determined by where you will have the test performed. You may have to do the following things:
  2. Cleaning your hair the evening before while staying away from hair chemicals, oils, and lotions.
  3. Getting a good night's sleep each night before.
  4. If you wear spectacles, make sure to bring them to the test with you.
  5. Before the test, you should be able to eat a regular meal and consume your regular medications. Any drugs that may cause drowsiness, on the other hand, should be avoided.
  6. Be on time and attempt to unwind before the exam.
  7. Tell the technician if you have any eye disorders, such as cataracts or glaucoma, on the day of the test, as this can impair the exam and should be documented in your files by the doctor. 

During a VEP eye test, what occurs?

-The process is extremely safe and painless.

-To begin, electrodes will be attached to the base of your skull to detect brain waves.

- You will be given more directions on what to do during the test by a professional. In most cases, each eye is checked separately.

- It's critical that you cooperate with the professional performing the exam and that you can fix your eyesight in a specific location. You'll be asked to stare at a screen that looks like a television screen but has different visual patterns on it.

-The electrodes on top of your head will be used to record the readings.

-The adhesive and cables are withdrawn from your skull after the surgery.

-After the test results have been analyzed, the doctor may discuss them with you; otherwise, the recommending doctor will.

-The treatment usually takes 45 minutes. 

VEP Test: Negative effects

This technique has very few negative side effects. The operation is painless, and there are usually no side effects other than slight skin rashes from the electrodes. If you have a medical condition like seizures, the visual stimuli you're exposed to are unlikely to cause seizures. However, this should be discussed with your physician and specialist before undergoing a VEP test.

Patients usually return home the same day as the treatment is completed. If you feel good following the surgery, you should be able to get home securely.

VEP is influenced by several factors.

Movement near the margins of your main visual fields is particularly sensitive to the cells in the area of your brain associated with vision. If you have weak vision, it does not appear to affect the response too much – larger checkered patterns can be employed instead. Additional factors that can influence the VEP include your gender, age, and pupil size. Your VEP will be substantially altered if you have taken any sleepy drugs or are under the effect of any aesthetic drugs.

Results: Possibilities

The VEP is very beneficial for detecting optic neuritis that has already occurred. This is an inflammatory of the optic nerve that is accompanied by inflammation and the gradual destruction of the nerve's sheath and, in some cases, the nerve cable. Because the neural sheath is destroyed, it takes longer for electrical impulses to reach the eyes, resulting in an aberrant VEP. Multiple sclerosis (MS) is one of the most likely reasons of peripheral neuropathy.  Because of the existence of optic neuritis, people with multiple sclerosis have abnormal VEPs. The minimum VEP test price is INR 1800.

The following are more difficult to distinguish yet may generate aberrant VEPs:

  • Optic neuropathy is a condition in which the optic nerve is damaged owing to a variety of factors such as a blockage in the nerve's blood flow, nutritional inadequacies, or pollutants. Electrical impulses do not flow properly as the neuron is destroyed. For example, severe diabetes can cause damage to blood vessels and neurons feeding the eyes, or toxic amblyopia, which is a vision loss condition caused by a toxic reaction in a portion of the optic nerve.
  • Tumours or lesions squeezing the optic nerve — when the optic nerve is squeezed, the conduction pathway is disrupted, resulting in an aberrant VEP.

Depending on the labs from where you get tested, VEP test cost ranges between INR 1800-5000. Get your eyes tested now.