Okay, this is nothing urgent. I just don't know where else to ask. It is rather a trivial matter, but here goes:
When using the variable $z$, seen most frequently in complex analysis questions: $z$ ALWAYS appears to me as less bold than the other variables, a mere silhouette compared to other letters and/or characters in a give expression. When it appears next to, say, $x, y$, the other characters stand out much more clearly than does $z$.
I also have a very pronounced astigmatism, which might explain how I perceive given letters, and it may be that $z$ happens to be shaped in a way that my astigmatism impacts my perception of the character.
But I have no problem with seeing z, only $z$!
I can see "$z$", it's just more faint than other characters.
(I need to add a tag, so I am adding "bug", but the "bug" might be my eyes.)
I just wanted to check in to see if any one else perceives the same, so I know if it's ME or MathJax!