Medical Policies - Other

Visual Evoked Potential Testing for Glaucoma


Effective Date:10-15-2017



Visual evoked potential (VEP) testing for glaucoma is considered experimental, investigational and/or unproven.

NOTE: This policy does not address the following:

Diagnosis/monitoring of multiple sclerosis;

Evaluation of visual loss in patients who are unable to communicate;

Localizing the cause of a visual defect not explained by computed tomography, magnetic resonance imaging, metabolic disorders, or infectious disease; or

Routine screening of infants.


Visual evoked potential (VEP) is a measurement of the electrical signal recorded at the scalp of the occipital cortex of the brain in response to visual light stimulus (e.g. checkerboard pattern, horizontal grating, vertical grating, flashes, monochromatic pattern onset, or color pattern). The light-evoked signal, small in wave peaks and hidden within the normal electroencephalogram (EEG) signal, is enlarged by repetitive stimulation and time-locked. When the response is delayed, the interpretation is that there are possible mechanical or neural abnormalities.


Glaucoma is a group of eye diseases which result in damage to the optic nerve and vision loss. The most common type is open-angle glaucoma with less common types including closed-angle glaucoma and normal-tension glaucoma. Open-angle glaucoma develops slowly over time and there is no pain. Side vision may begin to decrease followed by central vision resulting in blindness if not treated. Closed-angle glaucoma can present gradually or suddenly. The sudden presentation may involve severe eye pain, blurred vision, mid-dilated pupil, redness of the eye, and nausea. Vision loss from glaucoma, once it has occurred, is permanent.

Risk factors for glaucoma include increased pressure in the eye (intraocular pressure [IOP]), a family history of the condition, migraines, high blood pressure, and obesity. Diagnosis is by a dilated eye examination. Often the optic nerve shows an abnormal amount of cupping. If treated early it is possible to slow or stop the progression of disease with medication, laser treatment, or surgery.

About 11- to 67-million people have glaucoma globally. The disease affects about 2.2-million people in the U.S. The number in the U.S. is likely to increase to 3.3-million in 2020 as the population ages (1) It occurs more commonly among older people. Closed-angle glaucoma is more common in women. Glaucoma has been called the "silent thief of sight" because the loss of vision usually occurs slowly over a long period of time. Worldwide, glaucoma is the second-leading cause of blindness after cataracts.

VEP testing for glaucoma is done to detect if the increased IOP has slowed/prolonged the response time from the visual stimulus to recording in the occipital cortex and may indicate damage to the optic nerve.

The stimuli are presented to the patient on a calibrated computer monitor at various numbers of elements in separately stimulated fields. The fields are varied in spatial size over a number of cycles. The fields are also phase reversed at different temporal frequencies. The signals are analyzed by the software algorithm for spatial/temporal filtering and artifact rejection. Data may be presented in numerical and graphical form. The device also utilizes attention grabbing features specifically for children or non-attentive adults. In particular, a picture is presented prior to the onset of the VEP pattern stimulus. During the picture presentation, no data is collected. Age appropriate music is also available to patient as needed as an attention facilitator. There are two devices available for infants and adults with the only difference between the devices is the software. VEP testing is done in the clinic or office setting.

Regulatory Status

Several VEP systems have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process. The Diopsys™ NOVA VEP Vision Testing System (Diopsys, Inc., Pine Brook, N.J.) received FDA approval on October 10, 2010. (2) The NOVA VEP device is substantially equivalent to the Diopsys™ Enfant® Pediatric VEP Vision Testing System and the VeriSci Corporation Neucodia® System, based on safety and efficacy. The NOVO VEP device is targeted for infants, pre-school children, children, and adults. FDA product code: GWE.


The policy was created in January 2017 from a MedLine search. The most recent literature review was performed through November 1, 2016. The following is a summary of the key reference to date.

One small prospective study, published in 2013 by Pillai et al., was carried out at the New York Eye and Ear Infirmary. (3) The study was industry sponsored to evaluate the ability of the short-duration transient visual evoked potential (SD-tVEP) and to discriminate between healthy eyes and eyes with early to advanced glaucomatous visual field loss. The control group included 30 eyes of 30 healthy individuals and 45 eyes of 35 glaucoma patients. SD-tVEPs were recorded using the Diopsys™ NOVA system. Each eye was stimulated with a low (Lc) and a high (Hc) Michelson contrast checkerboard pattern. Each test resulted in an Lc and an Hc SD-tVEP response. Each response was evaluated for overall waveform quality, P100 latency, and P100 amplitude referenced to the N75. The sensitivity, specificity, negative predictor value (NPV), and positive predictor value (PPV) were calculated. Lc latency showed the highest accuracy for discrimination using receiver operating characteristic curves for high and low contrast parameters. The analysis for all subjects resulted in a 91.1% sensitivity, 93.3% specificity, 95.3% PPV, and an 87.5% NPV. Evaluating the mean Lc latency of the mild, moderate, and severe glaucoma patients against controls showed discrimination consistent with the glaucoma severity. The authors concluded SD-tVEP objectively identified decreased visual function and discriminated between healthy and glaucomatous eyes, and also showed good differentiation between healthy eyes and those with early visual field loss. VEP may be useful for early diagnosis of glaucoma.

Ongoing and Unpublished Clinical Trials

A search of on October 31, 2016 identified no clinical trials that would influence the coverage position of this medical policy.

Clinical Practice Guidelines and Position Statements

American Academy of Ophthalmology (AAO) and American Glaucoma Society (AGS)

The 2011 AAO and AGS Joints Comments “Comparative Effectiveness of Screening for Glaucoma” did not include VEP testing for glaucoma. (4)

National Institute for Health and Care Excellence (NICE)

The 2009 NICE Clinical Guidelines “Diagnosis and Management of Chronic Open Angle Glaucoma and Ocular Hypertension” did not offer support for VEP diagnostic evaluation or screening of glaucoma. (5)

Summary of Evidence

With only one published clinical study, the insufficient evidence of effectiveness cannot support the use of visual evoked potential testing for glaucoma. Further studies are warranted to determine if VEP is superior to current, well-established methods to test for the IOP of glaucoma. The absence of specialty societal guidelines or recommendations cannot support the use of VEP in the evaluation of glaucoma. Therefore, visual evoked potential testing for glaucoma is considered experimental, investigational and/or unproven.


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Medicare Coverage:

The information contained in this section is for informational purposes only. HCSC makes no representation as to the accuracy of this information. It is not to be used for claims adjudication for HCSC Plans.

The Centers for Medicare and Medicaid Services (CMS) does not have a national Medicare coverage position. Coverage may be subject to local carrier discretion.

A national coverage position for Medicare may have been developed since this medical policy document was written. See Medicare's National Coverage at <>.


1. AAO – Visual Evoked Potential (Clinical Education) (2016). Prepared by the American Academy of Ophthalmology. Available at: <> (accessed 2016 October 31).

2. FDA – Diopsys™ NOVA VEP Vision Testing System (Product Information – October 10, 2010). Prepared by the U.S. Food and Drug Administration. Available at: <> (accessed 2016 November 2).

3. Pillai C, Ritch R, Derr P, et al. Sensitivity and specificity of short-duration transient visual evoked potentials (SD-tVEP) in discriminating normal from glaucomatous eyes. Invest Ophthalmol Vis Sci. Apr 2013; 54(4):2847-52. PMID 23513061

4. AAO – American Academy of Ophthalmology and the American Glaucoma Society Joint Comments on: Comparative Effectiveness of Screening for Glaucoma (October 12, 2011). Prepared by the American Academy of Ophthalmology. Available at: <> (accessed 2016 October 31).

5. NICE – Glaucoma: Diagnosis and Management of Chronic Open Angle Glaucoma and Ocular Hypertension (NICE Clinical Guideline 85, Issued April 2009). Prepared by the National Institute for Health and Care Excellence. Available at: <> (accessed 2016 October 31).

Policy History:

10/15/2017 Reviewed. No changes.
1/1/2017 New medical document. Visual evoked potential (VEP) testing for glaucoma is considered experimental, investigational and/or unproven.

Archived Document(s):

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