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Transl Vis Sci Technol. 2017 Nov 8;6(6):6. doi: 10.1167/tvst.6.6.6. eCollection 2017.

Pattern Electroretinography and Visual Evoked Potentials Provide Clinical Evidence of CNS Modulation of High- and Low-Contrast VEP Latency in Glaucoma.

Author information

WESMDPA Baptist Medical Center Glaucoma Service, San Antonio, TX, USA.
Vision Sciences, University of the Incarnate Word Rosenberg School of Optometry, San Antonio, TX, USA.
Department of Biomedical Engineering, University of Texas San Antonio, San Antonio, TX, USA.
Diopsys, Pine Brook, NJ, USA.
Ophthalmology, Stanford University, Stanford, CA, USA.
Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.



Both pattern electroretinography (PERG) and visual evoked potentials (VEP) can be performed using low- (15%; Lc) and high- (85%; Hc) contrast gratings that may preferentially stimulate the magno- and parvocellular pathways. We observed that among glaucomatous patients showing only one VEP latency deficit per eye, there appeared to be a very strong tendency for an Hc delay in one eye and an Lc delay in the other.


Diopsys NOVA-LX system was used to measure VEP Hc and Lc latency among a clinical glaucoma population to find all individuals with either a single Hc or Lc latency abnormality in each eye (group 1), or with greater than 0 and less than 4 Hc or Lc VEP latency abnormalities in the two eyes (group 2) to determine whether a significant inverse correlation existed for these values in either group. Hc and Lc PERG data were also evaluated to assess associated retinal ganglion cell responses.


A strong inverse correlation (P = 0.0000003) was observed between the Hc and Lc VEP latency values among the 64 eyes in group 1. Group 2 provided a comparable result (n = 143; 286 eyes; P = 0.0005). PERG (n = 81; 162 eyes) also showed strong bilateral symmetry for magnitude values (P < 0.0001 for both Lc and Hc in groups 1 and 2).


Bilateral retention of both low-resolution/high-speed and high-resolution/low-speed function may persist with both eyes open despite symmetrically pathologic retinal ganglion cell PERG waveform asynchrony for Hc and Lc stimuli in the paired eyes.

Translational Relevance:

Clinical electrophysiology strongly suggests binocular compensation for dynamic dysfunction operates under central nervous system (CNS) control in glaucoma.


central visual pathways; magnocellular/parvocellular; pattern electroretinogram; pattern visual evoked potentials; visual field

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