Night Blindness-like symptoms, are these curable?

I always didn't have the best eyesight; my right is at 0.4, while my left is 0.1 or lower. However, I have always made do with glasses, and I didn't notice any deterioration of my vision whatsoever.

Recently, I've been noticing something that definitely wasn't there about a month ago; I can barely see in dark areas. For example; when stargazing, I used to be able to see the stars perfectly normally, but now I can barely see the brightest ones. When I look towards grounded objects, I can see their outlines silhuetted against dim light but I can't discern ones that don't have background light. When I'm "night blinded", I also seem to see something not unlike the distorted shapes moving around when you close your eyes, which blocks most of the light.

Furthermore, I seem to have a black disk made up of those moving, slightly colored shapes blocking my intermediate vision. I can discern objects at the edge of my peripheral vision just like I used to, and I can see objects in about a 5 degree circle in the middle of my sight, but everything else is clouded with the shapes. However, the size of this disk is about the size of my glasses; perhaps this has something to do with wearing glasses for an extended period of time?

I should add that I have absolutely no change in my vision strength at medium to high light, and I don't get "blinded" easily by dark to light transitions. Furthermore, even in dark areas I can see areas lit by streetlamps as usual, without the dark shapes blocking my way.

What is this, and is this curable?

Do you have cataracts developing?

I don't think so; my vision is clear, and the only time the vague dark material impedes my sight is at night when there are no very clear lights around.

Have you had your eyes tested recently?  Perhaps you should go again