ERG and VEP by Metrovision

Pattern ERG and VEP

Constant luminance cannot be achieved with standard LCD monitors

One important characteristic of pattern stimulations is that the average luminance should be constant (ISCEV standards for pattern ERG and for pattern VEP).
There should be no change in luminance, even transient when reversing the stimulus or when switching from the "on" to the "off" pattern.
If constant luminance is not achieved, the PERG stimulus generates a response not only from the ganglion cells but also from other layers of the retina. In a similar way the PVEP stimulus activates different types of cortical cells. This may results in a diagnosis error.
Standard LCD monitors produce a transient light flash at each pattern reversal or pattern on-off. This is due to a different velocity of the liquid crystals between the on-off and off-on transitions.

• More information about the luminance artefact Information Request

Pattern ERG and VEP

Metrovision has developped a proprietary technology that generates stimulations with constant luminance.

Metrovision's patented technology involves the use of a LED backlight monitor. A light sensor constantly measures the luminance output and adjusts the backlight in real time so as to achieve constant luminance.

• MonPackONE PDF brochure

Flash ERG and VEP on MonPackONE

MonPackONE generation of ganzfeld stimulations

In the ganzfeld mode, flashes of light are produced by LEDs from the backlight and from the surrounding to produce a full field uniform illumination of the eye.
MonPackONE uses LEDs with 3 different wavelengths. Each of them can be programmed over a dynamic range of 5 log units. They can be combined to produce white light or any combination of 8 million colors.

• MonPackONE PDF brochure Information Request

Flash ERG and VEP on MonCvONE

MonCvONE generation of ganzfeld stimulations

The MonCvONE perimeter, version CR++ can perform the entire ISCEV flash ERG protocol, as a simple addition to the perimetry testing functions.
In combination with the MonPackONE, it is the most advanced visual function testing system available today.

• MonCvONE-CR PDF brochure Information Request

Flash ERG and VEP on MonColor

MonColor generation of ganzfeld stimulations

Moncolor uses LEds with 5 different wavelengths producing a uniform illumination of the eye. They can be conbined to produce white light or any combination of 8 billion colors.
It can also generate specific stimulations for the study of S-cone (violet over amber) and L-cone (deep red) responses.
MonColor can be combined to MonPackONE and MonBaby, resulting in an advanced electrophysiology unit

• MonColor PDF brochure Information Request

Statistical analysis of reliability

The first step in the interpretation of evoked responses is the evaluation of reliability

Metrovision's exclusive test of reliability indicates in a simple way if the response is significantly different from "noise".

Statistical analysis of normality

Comparison with a normal data base

A second step in the interpretation of evoked responses is the comparison with normals.
This is accomplished automatically and the result is given as a color code based on the p-value.
(* normal values are given for a specific set of test parameters. If different parameters are used, normal values can be defined by the user)