As far as I know, only creationists, panpyschists and solipsists content that outside reality is contingent on consciousness. Realists and antirealists alike distinguish between reality and epistemology, between what reality is and what humans can know about it. But the human ability to know is real in its own right.
What happens when some aspect of reality enters into my conscious awareness? Say I realize that it’s raining outside. It was already raining before I realized it. I might even have been subliminally aware of the sound of the rain falling on the windows. But now that sound has crossed the threshold into consciousness, and I think: it’s raining. The rain has now had an impact on my consciousness. I don’t have to create a mental representation of the rain, so that a mental image of the rain is created in my mind as a sort of shadow reality. My consciousness operates as a kind of rain gauge: its change of state — a new awareness that it’s raining — points to the presence of something real happening in the world. The rain registers its already-existing reality by changing the state of my conscious awareness, just as it did earlier to my window and to my auditory sensory apparatus. The rain has extended its sphere of influence, the extent to which it makes differences happen in the world.
The rain causes these changes of state in the world, but the changes happen to the window, to my audition, to my consciousness. The window is percussed and covered in water; my ear and brain hear new sounds; I think a new thought: these changes are real and distinct in their own right, apart from their common cause. In its interaction with the external reality of the rain, my consciousness demonstrates its own reality.
This description regards consciousness as a kind of object, a recording surface not unlike a window. And in many ways the brain is that sort of object — a congeries of neurons and synaptic connections physically located in the central nervous system. But consciousness isn’t just the static state of the brain; it’s more like a device that keeps track of changes in brain state. Some of these brain-state changes are triggered by changes in the state of the environment. Changes in brain state result from changes in brain processes: the auditory sensory input triggers activation of the “it’s raining” thought that’s already associated in the cerebral network with this kind of sound. Of course consciounsess often takes a more active role, but a major aspect of its own reality is its ability to detect external reality.