Very good observation. This is why, I believe, staring at the entopic lights before sleep causes spontaneous lucidity later on that night. If you are able to fully grab your feelings on the connection you just have discovered, let's say by contemplating on this connection or just feeling it, you will have a better chance at this exercise. The most important thing however is to go back to the light patterns every time you catch up on yourself that your thoughts have drifted away. Sometimes, right after coming out from a brief dream or hypnagog vision, you will see a luminous blob at the center of your vision field slowly fading away. A very good sign!