It does not offhand sound like an eye problem to me. Eye problems
typically give you anomalies at the same location in the retina,
meaning that they will follow your eye movements so as to stay in
the same location in the scene as you see it, even though you are
moving about looking at different things.
Descriptions of orbs have sometimes included colored lights that
move around the room. If these shapes move separately from the
movements of your eyes, that would seem to say it is not an eye
problem. There are a few eye problems, like "floaters" that have a
little independent movement, but they still follow the eye.
Google has a lot on the shadow people.
Art bell and George Noory of the Coast to Coast AM radio program
have had a number of programs on the shadow people. Listeners call
in and describe that they see shapes out of the corner of their
eyes that disappear when they look right at them. I have a CD from
that program, with collections from past programs, but I have not
looked into it yet. If I come across that subject I will post it.
Visiting spooks assume that you cannot see them, if they are just
looking around, not intending to be seen, and are startled when you
appear to be seeing them.
There have also been descriptions of apparitions that are "blacker
than black", meaning that the black shape is superimposed on the
background.
This web site is a place where you can begin the journey to
overcome your fear of death. You could also begin to read the
Near Death Experiences on
www.near-death.com Most of these experiences are not to be feared. There, you can find
out what to expect instead of fearing the unknown. Many of the
survivors had such great experiences that they did not want to come
back to life.
It might take some test on your part to see if these apparitions
are friendly or unfriendly. If they persist, you might try to talk
to them. You might want to use prayer to psychically protect
yourself, in case they are unknown. Some spirits will fear the name
of God or Jesus. That is a larger subject to go into.
At least, you now know you are not alone, and might have no
reason for great concern. I do not recall the shadow people being
dangerous.