A couple of times recently during meditation I've had a similar experience, and it's seemed as if I can see through my eyelids. This is all pretty new to me too, so I'm going to keep working on it and see where it goes.
The comment about meditation being like a muscle ring true with me. I find that if I don't meditate for a while it takes me a few sessions to get back into it, and with each session I feel like it's easier to reach a deeper state. One of my intentions for the year is to make meditation a twice-daily exercise so that I can really develop this deeper feeling rather than just 'skimming along the surface' like I have been up until now.