Also, this subreddit has many information and anecdotal experience on this technique: https://www.reddit.com/r/CureAphantasia/
I have seen some shapes and a few colors for now. Most importantly, I have started to see vivid dreams in the last few days, which has never happened before (before that it was just a feeling not a visual. However, my father suggested this might just be that I have learned to remember dreams more by becoming more conscious about it, which is a possibility). It's too soon to judge. So, I'll keep doing it for a couple more weeks to see if it can help me see visuals rather than random flashes.
If you are interested in internal visions, try flickering lights with closed eyes. Around 10hz they create strong internal visuals after about a minute. There are several apps that can do this— luminate is one, but there are free ones, too.
(Usual warnings about photosensitive epilepsy apply)