Frequently Asked Questions &


Frequently Asked Questions

Why Fourier analytics?

Fourier TransformTraditionally, visual electrophysiology data has been analyzed in the time domain, typically with a transient response, looking at one or two peaks to try to draw conclusions as to whether or not the response is affected. EvokeDx features a discrete Fourier transform from the time domain to the frequency domain, allowing data from the entire response to be included in the analysis.

Much as when OCT leaped from the time domain to the spectral domain, an entirely new set of statistical tools are available in the frequency domain to simplify the clinician’s assessment of VEP and ERG responses.

EvokeDx is designed for visual electrophysiology measurement.  This includes VEP, ERG, and our proprietary icVEP test strategy that was the subject of an NIH funded, multi-center clinical trial.  icVEP is a low-contrast, high temporal frequency pattern that sinusoidally varies in contrast at 10 Hz.  With a well functioning pathway, and the Fourier Transform, we expect to measure a sinusoidal variance in signal at exactly 10 Hz at the visual cortex.

This novel test strategy is available in three variants: single contrast bright check, sweep of contrasting, bright checks, and sweep of contrasting dark checks.

EvokeDx libraryEvokeDx features multiple visual electrophysiology test configurations with commonly used parameters for icVEP, VEP, and ERG.

Visual electrophysiology has been performed for decades using a large assortment of EEG sensors, both generic and speciality, built to gather as large as possible amplitudes in the least invasive manner (something that is generally mutually exclusive).  Konan strategically utilizes standard snap connectors to give our customers a choice, both now and in the future, of the types of electrodes selected.  Use of a proprietary connector would have locked you into purchasing single-supplier, high-cost products.

The standard EEG skin electrodes used for ERG testing are easy to prep for, apply, and also provide good signal amplitudes.

Our gaze monitoring system provides an on-screen video feed of the patient for the technician to easily monitor test progress and patient attention.  Inattention, excessive blinking, and closed eyes will distort the collected data.  Prompt attention to attentiveness will mean fewer test repeats, happier patients and better office efficiency.

EvokeDx will record one or two channels of data.  With a 5-wire lead cable, a patient can be easily prepped to do bilateral ERG recordings in a single go.

Most Konan Medical products come standard with a permission-based, encrypted, remote access tool for on-request customer support. This feature of KonanCare provides our customers with expert technical and clinical assistance without the need for an on-site visit.  KonanCare remote access is invaluable for staff training, hardware and software troubleshooting, and assistance with clinical interpretation.

EvokeDx compare functionEvokeDx’s “Compare” tool allows you to overlay two different exams to simply visually assess a change or difference. The Compare tool is useful to assess right versus left eyes at the same visit, or same eye over time.

Note that EvokeDx data is protected by 256-bit encryption and is HIPAA compliant.

Many early-adopter practices purchased (and often fully paid for) first-generation clinical electrophysiology devices. Just as purchasers of time-domain OCT devices found the expanded applications and robust assessment features clinically important enough to justify moving to a spectral domain system, our customers are echoing this with EvokeDx.

Another important consideration may be the ongoing costs of disposable products. If you have a first-generation device and find yourself annoyed with the high monthly electrode and cable replacement costs, and really wish that there were better analytic tools for clinical assessment available, contact sales@KonanMedical to get a tailored estimate of the real costs of ownership.
EvokeDx uses the same network-based file naming and location convention successfully used with our CellChek systems in thousands of clinical settings. A DICOM client is in the development pipeline.

Absolutely.  Some first-generation systems may not have adequate safeguards for data protection to HIPAA requirements, and the doctor may have unintended liability for this non-compliance.


OLED stimulus display
Premium specification, with linearization and microsecond timing, successfully addresses luminance artifact contamination known to affect LCD displays
NIH clinical data
Multi-center clinical study: differentiation of glaucoma and normals with icVEP-LC 1
All-in-one design
Beautiful, compact, delivered in one box, and can be mobilized with optional case
Patented icVEP test strategies
Low Contrast Bright (single step), Bright Sweep, Dark Sweep
Gaze monitor
On-screen gaze monitoring allows operator to easily monitor both test recording and patient attention
Test library
16 different icVEP, VEP, ERG
EvokeDx Viewer
Viewer application allows secure remote access by physician to test results on device
Touch-screen UI
Double-shielded, internal amplifier ... no need for the patient to hold parts of the test equipment
Fourier transform analytics
T2circ, Sine : Cosine, Amp-Phase, and MSC
Single or dual channel recording
Record single channel (3 lead) or bilateral ERG or simultaneous VEP & ERG (5 lead) ... in one go!
Very short interval testing
Test is divided into multiple short sequences typically 2 to 6 seconds each
Luminance calibration
Simple (auto and semi-auto) calibration, linearization, and calibration history
Child-attention animations
Selectable high-quality videos to capture and hold attention
Synchronous data collection
Data collection is synchronized using low-latency Polling technique (non-IRQ) with the stimulus frame rate to eliminate time gap shifting and enhance Fourier transformed calculations
Auditory cues for patient
No sound (or associated data contamination) from intra-test sound files
Low-cost, disposable electrodes
Other systems may require costly, proprietary electrodes ... EvokeDx uses low-cost solutions for patient disposables.
EMR | EHR  Local or network reports configuration 
Simple software upgrades    Software is easily kept current with either on-request or on-screen notice of a new version 
Integrated data backup 
Local or network locations 


1920 x 1080
Patented isolated-check, checkerboard, gratings, windmill-dartboard, uniform field
Frame rate
60 Hz
 Temporal functions
Sine wave, square wave, superimposed two sinusoid
Grey level
8 bit resolution
Sweep display
Up to 10 steps with variable contrast, spatial frequency, and
temporal frequency
Gamma correction

Analog - digital
16 bit resolution
Data-timing control
Low-latency Polling method (non-IRQ) to synchronize data collection to stimulus frame rate to decrease variability in response measures
Sampling rate
480 S/s
3 and 5 with disposable AgCl
SIGNAL AMPLIFICATION - meets or exceeds ISCEV - International Society for Clinical Electrophysiology of Vision and FDA regulatory requirements
Differential, One or Two
Fourier bandwidth 0.5 to 100 Hz, Fourier notch filter
Input range
+/- 6 mV
Common Mode Rejection
Ratio > 120 dB
Input impedance
2 X 1012
Ohm isolation voltage 1.5 kV Power supply
+8 to +15 VDC
Steady-state response
Spectrum analysis
Digital Fourier Transform driven statistical analysis reducing complex waveform to amplitude and phase angle
Transient response
Artifact removal
Coherence (Magnitude Squared Coherence) of recorded response
compared to frequency response noise
Digital filters
Low, high, even/odd, notch
Statistical definition of difference between two samples and confidence interval
Integrated computer
Operator: 22" touchscreen
100-240 VAC; 50/60 Hz; 5.5 A; isolation transformer included
Gaze / eye monitoring
Infrared 770-950 nm camera (ISO grp)
WiFi / bluetooth
Printing, EMR network communications, secure support
20.7 x 9.5 x 16.4 inches W x D x H (52.6 x 41.6 x 16.2 cm)
50 lbs (22.7 kgs)
FDA 510(k) K081591 5
Certificate # 229AGBZX00100000 (COSMOS CORP)
CE mark

1. US Patent 06966650: Method and Apparatus for and Automated Procedure to Detect and Monitor Early-stage Glaucoma. 2. Victor JD, Mask J. A new statistic for steady-state evoked potentials, Electroencephalogy Clin Neurophysiol, 1991, 78:378-388. 3. Zemon V, Tsai JC, et al. Novel electrophysiological instrument for rapid and objective assessment of magnocellular deficits associated with glaucoma, Doc. Ophthalmol, 2008, 17:233-243. 4. Kim D, Zemon V, Saperstein A, Butler B, Javitt D. Dysfunction of early-stage processing in schizophrenia: harmonic analysis, Schizophr. Res, 2005, 76:55-65. 5. FDA 510(k) K081591. This device is used as a tool for assessment of visual function. It cannot be used as a definitive diagnostic indicator. The configuration and interpretation of the test shall be made by users based upon their knowledge and understanding of VEPs in response to stimuli. Diagnosis of a patient is the responsibility of a licensed physician.