I'm sure there are many people here to comment on the more metaphysical aspects of your post; let me mention some aspects of the physiology of the
eye, normally unnoticed, that are sometimes revealed during meditation.
The eyes are almost never completely still, even when you think you're staring at a fixed point. There are small, very fast (typically less than 10
milliseconds) oscillations called
microsaccades. One thing they do is slightly vary the visual
input presented to adjacent rod and cone cells on the surface of the retina. Without this variation, the eye quickly becomes adapted to edge and fine
detail in the visual scene, and it, perceptually, 'disappears'.
This phenomena also occurs with voluntary eye movement, on larger consistent fields of color. That's called chromatic adaptation. Here are some
example pictures to illustrate the effect:
1
2
Also, when the eye is moving over a scene, the information from the retina is interpreted differently by the brain. Otherwise, blurring or bright
flashes of light could confuse the perception! This is called
saccadic masking.
So, one thing I would suggest, that you have apparently already started doing, is to take notice of how the behavior of your visual system changes
during meditation. That could help explain these 'tints' you see -- conscious suppression of saccadic masking, perceptual tinting from color
adaptation due to a change in microsaccade frequency, are all things to consider.