Evaluation of Pre-perimetric Glaucoma Patients using Short Duration Transient Visual Evoked Potentials (SD-tVEP)

Abstract

Purpose: To evaluate the response of the Short Duration Transient Visual Evoked Potentials (SD-tVEP) on patients with pre-perimetric glaucoma (PrG).

Methods: Inclusion criteria were best corrected visual acuity of 20/30 or better normal 24-2 SITA-Standard visual fields (VF) in patients with glaucomatous optic neuropathy. Pre-perimetric glaucoma was defined by the presence of significant retinal nerve fiber layer thinning measured by spectral-domain optical coherence tomography (Spectralis, Heidelberg) whereas normal subjects (control group) had no abnormalities on this test. SD-tVEPs were recorded using the Diopsys NOVA System (Diopsys, Inc. Pine Brook, NJ). Each eye was stimulated with a 15% (Lc) and 85% (Hc) Michelson contrast checkerboard pattern. Test duration was 30 seconds/eye and each test resulted in a low- and high-contrast response. Each response was evaluated for overall waveform quality, P100 latency, and the amplitude difference of the P100 and N75. The two AUC-ROC analysis was performed on the both the Hc and Lc SD-tVEP parameters.

Results: 36 PrG patients and 30 controls with normal eyes were enrolled. There was difference in SD-tVEP Lc latency parameter between cases and controls (P=0.0032). Evaluating the SD-tVEP Lc parameters, the AUCs were 0.72 (0.59-0.86) for P100 latency and 0.58 (0.44-0.72) for P100 amplitude. Evaluating the SD-tVEP Hc parameters, the AUCs were 0.68 (0.55-0.81) for P100 latency and 0.58 (0.44-0.72) for P100 amplitude.

Conclusions: The low contrast SD-tVEP latency parameter produced the greatest AUC. The SD-tVEP low contrast latency parameter was able to differentiate normal and PrG patients and may be useful for the diagnosis of glaucoma with structural abnormalities but normal achromatic perimetry.

Keywords: 507 electrophysiology: clinical • 531 ganglion cells