ATTENTION: NOT A TEACHER
(1) As you know, a "chamber" means a room or a space.
(2) Thus, we might say that a "reality chamber" is that "space" in your mind
where you decide what is "real" and what is "wishful thinking."
(3) "Heightened," as you know, means something like "stronger." For example,
you know that something horrible happened on September 11 ten years ago in
New York City. Well, the police in New York City are on heightened alert. That is,
they are always on alert (looking for), but today they are more strongly/deeply on alert.
(4) So we might say that a "heightened reality chamber" means something like a
super reality chamber.
(5) In plain English, we might interpret the first sentence something like:
The sudden loss of sight forced me to accept brutal reality. (No more lying to myself.
I had to accept that everything was now changed and that I had no choice but to
make changes in order to deal with the new realities of my existence.)