Nearsightedness, astigmatism and color

Factual Questions
1

I’m hoping some ophthamology/optometry/optics geeks here can answer this.

I’m nearsighted with severe astigmatism. I have progressive lenses because I’m also slightly farsighted. I’ve noticed the following at night:

Through my glasses white, red and yellow lights are in focus. Green lights are fuzzy. Blue lights are decidedly fuzzy and if they are a dark blue/purple, almost unresovable against the background. Mercury lights which are mainly white are in focus, but have a blue ring around them.

When I take off my glasses everything changes into a field of puffy lit chrysanthemums, so I can’t really ascertain whether or not blue lights are worse than red lights.

In the daylight none of this is a problem. I’m wondering-- is this the lens? My eyes? What’s causing this phenomena to happen?

2

Yes, it’s a shortcoming of the lenses. Simple lenses, as found in eyeglasses can’t compensate for the change in refractive index as the wavelength of the light changes. Red is bent more than green light, which in turn is bent more than violet light. Normally this isn’t noticeable, but in your case, you apparently have a very strong presciption with a large curvature, which enhances this effect. Incidentally, this is the same reason that a prism can split white light into its component colors. Your optometrist may be able to alter your presciption to compensate.

3

I am severely shortsighted and also astigmatic.

My left eye is better than my right eye in terms of overall power, although the astigmatism is similar.

My left eye sees colour with more contrast that my right - colours are sharp and tend to “black and white” even without glasses.

My right eye sees colour richer and deeper, I can see this by closing one eye, then the other.

I don’t know if it’s due to the powr of my eye’s lens but what a coincidence…