Changing the colour scheme to high contrast colours can help improve legibility and make it easier to use the menus. You can change this in the settings menu:
Bring up the menu on your remote
Scroll down to the Accessibility & Language area and select Appearance
Select High contrast colours
Change this to On
*Depending on your box model, Settings will be on the last tab on the Main Menu or in a cog in the top right corner of the screen. You can get to the cog by pressing Up after opening the Main Menu. If you have the new Home Screen, you can access settings by pressing Up and then right after opening the home screen.