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Dilru Amarasekera, ARTHUR RESENDE, Michael Waisbourd, Lisa A Hark, L. Jay Katz, Anand V Mantravadi; Two Novel Electrophysiological Diagnostic Tests for Detection of Reversal of Retinal Ganglion Cell Dysfunction in Ocular Hypertension Patients. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5844.
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© ARVO (1962-2015); The Authors (2016-present)
Retinal ganglion cell (RGC) dysfunction is one of the earliest signs of glaucoma. Though structural and functional changes in the optic nerve have been noted following intraocular pressure (IOP)-lowering therapy, few studies have confirmed reversal of RGC dysfunction. We aimed to determine whether two electrophysiological tests, steady-state pattern electroretinogram (ss-PERG) (Diopsys Inc., Pine Brook, NJ) and short duration transient visual evoked potentials (SD-tVEP) (Diopsys Inc., Pine Brook, NJ), could be used to detect reversal of RGC dysfunction after IOP reduction in participants with ocular hypertension (OHTN).
Participants with OHTN (IOP>22 mmHg, normal optic discs and visual fields) underwent ss-PERG and SD-tVEP testing at baseline and again 3 hours after administration of bimatoprost and brimonidine. Two ss-PERG stimuli, 64-bar size and 32-bar size, both with low contrast (Lc) and high contrast (Hc) settings were used. Parameters compared before and after treatment were MagnitudeD, MagnitudeD/Magnitude, and the signal-to-noise ratio (SNR). Two SD-tVEP stimuli, 32x32 checkerboard spatial frequency with Lc and Hc settings, were used to compare signal amplitude and latency at baseline and 3 hours after treatment.
Ten participants (18 eyes) with OHTN were tested before and after receiving IOP-lowering medications. Mean IOP was reduced from 23.8 mmHg to 17.6 mmHg following treatment (P<0.001). The SD-tVEP signal amplitude was found to be significantly higher in participants 3 hours post-treatment when using a 32x32 spatial frequency Lc stimulus (P=0.016). No other parameters were found to be significantly different when compared before and after IOP-lowering intervention.
The novel SD-tVEP test (32x32 spatial frequency Lc) detected reversible functional changes in participants with OHTN shortly after receiving IOP-lowering therapy. Further study is needed to investigate whether electrophysiological tests have a potential role in identifying participants with OHTN who may benefit from IOP-lowering therapy.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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