If you cannot detect the move radius
then your monitor is adjusted WAY too bright. It's that simple.
The darkened hexes are drawn from a parallel part of the palette from the "normal" colours. This is what the game should look like but it's usually a waste of time showing people who have this problem this becasue the example shows up just as badly when they view it becasue they are running their monitors so bright all the colours get washed out of the game.
The first time I saw this was at a friends house and was appalled at how poorly the game looked but he thought it was normal until I showed him what it looks like on my monitor. If the game seems "washed out" run the test on that link Cross posted and adjust your monitor and your problem will go away.
Now..... if this IS the way your game looks, and you still have trouble distinguishing the move radius, then yes, you
DO need glasses.
HERE is a website that shows the photo standards for a monitor.
However, the built in test I put on the "rebel" flags years ago is "close enough". You should
just barely see the diagonal line. If it's clear and distinct, your monitor is too bright ( enlarged version )
Don