I was seeing the golden ring, blue ring and star after my kriyas. Now I see only a bright single light encompassing all of my vision and go through it to indigo blue. Is this improvement or is something off?
It is wonderful that you were able to see the spiritual eye in all its radiant beauty and colors. Often in the beginning of our path or at certain points along the way, we receive these amazing gifts.
But the true test of meditation is not what you see or hear in meditation. It is rather how you are changing as a person in daily life.
Are you calmer under all circumstances? Are you able to stay centered in very stressful situations? Are you kinder? Evenminded and cheerful? These are the guideposts. The other "gifts" are just phenomena that come and go. Perhaps eventually they will come to stay, but meantime, nothing to be concerned about.
And nothing is "off" about seeing a blue field now going into indigo. Many things happen over the course of our many, many years of striving to meditate more deeply through the practices of Kriya Yoga.
Just enjoy what is happening now and keep going.
One thing I can pretty well guarantee. Things will always keep changing until they become changeless in your final state of oneness with God. Just resolve never to give up and keep asking God and Gurus to help and guide you through it all.