I am a 66 year old amateur of some years of experience. Of late I notice a dark object which appears in my vision when I view an out of focus star. In the drawing I have made, you see a disc of light of an defocused star, with the secondary shadow in the center. Note the dark area that almost looks like a bat with wings. When I rotate my head, the dark area rotates also. And while I am not seeking medical advice, has anyone seen anything similar to this? I do have moderate cataracts. And the vitreous humor has pulled away from my retina, but no retinal tear. This is not unusual at my age. Anyone care to help me identify what is going on here?