Multifocal Visual Evoked Responses to Dichoptic Stimulation Using Virtual Reality Goggles: Multifocal VER to Dichoptic Stimulation

Abstract

Multifocal visual evoked potentials (mfVEPs) have demonstrated good diagnostic capabilities in glaucoma and optic neuritis. This study aimed at evaluating the possibility of simultaneously recording mfVEP for both eyes with dichoptic stimulation using virtual reality goggles and also to determine the stimulus characteristics that yield maximum amplitude. ten healthy volunteers were recruited and temporally sparse pattern pulse stimuli were presented dichoptically using virtual reality goggles. Experiment 1 involved recording responses to dichoptically presented checkerboard stimuli and also confirming true topographic representation by switching off specific segments. Experiment 2 involved monocular stimulation and comparison of amplitude with Experiment 1. In Experiment 3, orthogonally oriented gratings were dichoptically presented. Experiment 4 involved dichoptic presentation of checkerboard stimuli at different levels of sparseness (5.0 times/s, 2.5 times/s, 1.66 times/s and 1.25 times/s), where stimulation of corresponding segments of two eyes were separated by 16.7, 66.7,116.7 & 166.7 ms respectively. Experiment 1 demonstrated good traces in all regions and confirmed topographic representation. However, there was suppression of amplitude of responses to dichoptic stimulation by 17.9+/-5.4% compared to monocular stimulation. Experiment 3 demonstrated similar suppression between orthogonal and checkerboard stimuli (p = 0.08). Experiment 4 demonstrated maximum amplitude and least suppression (4.8%) with stimulation at 1.25 times/s with 166.7 ms separation between eyes. It is possible to record mfVEP for both eyes during dichoptic stimulation using virtual reality goggles, which present binocular simultaneous patterns driven by independent sequences. Interocular suppression can be almost eliminated by using a temporally sparse stimulus of 1.25 times/s with a separation of 166.7 ms between stimulation of corresponding segments of the two eyes.

Multifocal pupillographic visual field testing in glaucoma

“…The random presentation, low stimulus presentation rates and small stimulus size mean that the stimulus should not produce ill effects in persons with photosensitive epilepsy, 49,50 although this has not been confirmed. Other problems that might affect the device tend to occur much less frequently than the 5–10% of patients who cannot complete a valid automated perimetry test 1,2,4,21 . That is, although problems such as floppy iris syndrome or extreme miosis may pose difficulties for mfPOP, these conditions present less often than the rate at which patients currently fail perimetry exams.…”

“…Other problems that might affect the device tend to occur much less frequently than the 5-10% of patients who cannot complete a valid automated perimetry test. 1,2,4,21 That is, although problems such as floppy iris syndrome or extreme miosis may pose difficulties for mfPOP, these conditions present less often than the rate at which patients currently fail perimetry exams.…”

“…Scalp recorded multifocal visual evoked potentials (mfVEPs) have been more successful. [15][16][17] Concurrent testing of both eyes with independent stimuli, dichoptic stimulation, is practical with mfVEPs, [18][19][20][21] but to date this has only been applied in two larger clinical studies. 22,23 The time required to set up and execute some mfVEP tests has been reported as 33 min.…”

Dichoptic Multifocal Pupillography Reveals Afferent Visual Field Defects in Early Type 2 Diabetes

“…17 Several studies have shown that multifocal (mf)ERGs can detect damage in mildly affected persons with diabetics. 18 -21 Also promising is dichoptic stimulation, which involves concurrent stimulation of both eyes with independent stimuli, which has been shown to work with mfVEPs, [22][23][24][25][26] and has been applied in clinical studies. 27,28 A drawback is that mfVEPs can take more than 30 minutes to set up and execute.…”

Virtual reality and augmented reality— emerging screening and diagnostic techniques in ophthalmology: A systematic review

“…provides a summary of the quantitative findings and important characteristics of these studies. To prove the feasibility of investigated measure, 3 and determine its effectiveness in detecting glaucomatous defects. 4 10 healthy volunteers 3 ; 28 glaucoma patients, 30 healthy subjects 4 mfVEP recording under VR dichoptic stimulation N/A 3 ; Monocular mfVEP and HFA 4 Feasibility of dichoptic VR stimulation and mfVEP recording is confirmed.…”