Purchase this article with an account.
L. K. Grover, P. Wynn, J. G. Odel, V. C. Greenstein, D. Xin, M. M. Behrens, D. C. Hood; Quantitative Analyses for Identifying Non-Organic Contributions to Visual Field Defects Using the Multifocal Visual Evoked Potential (mfVEP). Invest. Ophthalmol. Vis. Sci. 2010;51(13):1463.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To test a quantitative approach for using the multifocal visual evoked potential (mfVEP) to identify non-organic contributions to visual field loss.
51 patients (80 eyes) were previously determined to have non-organic contributions to their visual loss. These eyes fell into two categories: non-organic (43) and abnormal with a non-organic overlay (37). The non-organic contributions were diagnosed based upon a comparison of the depth, extent, and location of defects obtained with static automated perimetry [SAP (Humphrey, Zeiss)] to the amplitude and location of the local mfVEP responses. The mfVEP responses were recorded to a 60-element dartboard display as previously described. To objectively identify non-organic loss, a quantitative approach was utilized. The amplitude of local mfVEP responses (signal-to-noise ratio) was plotted versus the corresponding local SAP loss (total deviation in dB) for each of the 60 locations in the mfVEP display. The 95% confidence limits were determined from a group of patients with known optic nerve disease due to ION or glaucoma and without non-organic contributions. Based upon this scatter plot, patients were considered to have a non-organic contribution to their visual field loss if they had at least four points, with SAP losses of greater or equal to -5dB, that fell above the 95% confidence interval.
With the quantitative approach, the 80 tested eyes fell into four categories: non-organic (40), abnormal with a non-organic overlay (24), abnormal without a non-organic contribution (13), and normal (3). Thus, the quantitative approach failed to detect a non-organic component in 16 eyes (20%) identified previously as either non-organic (3) or abnormal with a non-organic overlay (13).
The mfVEP is useful in detecting non-organic contributions to visual field defects seen on SAP. A quantitative approach can be used to screen for non-organic field loss. However, if it is still suspected but not detected by this method, a closer examination of the SAP and mfVEP results can be employed to further rule out a non-organic contribution. 1. Hood & Greenstein (2002) PRER.
This PDF is available to Subscribers Only