Camera Matrix does not behave as expected

I try to render a simple grid using glBegin(GL_LINES).
I have a class Camera, which provides values like this:

  float farPlane = 100.0f;
    float nearPlane= 0.1f;
    float screenRatio = 1,42857; //width/height = 1000/700
    float frustum = 70.0f;
    glm::vec3 position = glm::vec3(3.0f, 3.0f, 3.0f);

    glm::vec3 UP = glm::vec3(0.0f, 1.0f, 0.0f);
    glm::mat4 view = glm::lookAt(position, position - glm::normalize(position), UP); // makes the lookAt vector always point towards (0, 0, 0)
    glm::mat4 projection = glm::perspective(frustum, screenRatio, nearPlane, farPlane);

using the view and projection matrices, i transform every vertex from my Grid model and render it.

    glm::mat4 viewProjectionMatrix = Graphic::camera->getViewProjectionMatrix(); // returns Camera::projection * Camera::view
    for (unsigned int i = 0; i < vertexNum; ++i) {
    	glColor3f(vertexArray[i].normal.x, vertexArray[i].normal.y, vertexArray[i].normal.z); // normal vector is used for color in this case
    	glm::vec4 translatedPosition(viewProjectionMatrix*gridTransformationMatrix*(glm::vec4(vertexArray[i].position, 1.0f)));
    	glVertex3f(translatedPosition.x, translatedPosition.y, translatedPosition.z);

but this is what i see when i move the camera along the line: (0,0,0) + u*(1,1,1)

(you can find the camera cooridnates in the console)

It appears as if it was not even perspective projection but orthographic.

That comma should be a period.

While GLM tends to mimic the legacy OpenGL matrix functions, one area where they differ is that GLM uses radians for angles whereas OpenGL uses degrees. (Actually, whether GLM uses degrees or radians depends upon the version and compiler switches; but modern versions use radians by default).