I have a question about eye caps that have lasted more than one shed.

My BP is a rescue and I dont know what conditions she was kept in prior (as i said in my intro post). She went a long time (3 months) without shedding and I thought that was because she might be near full grown. So she shed and retained her eye caps (a really broken shed) and I did not worry. Now about 1 month later, she shed again and the most partial shed I have ever seen and hardly anything off her head. So we fast foward to this past weekend and I went to feed her and I thought snakes did not hunt visually, but she could not catch that rat. I have never pre-killed or pre stunned because she has always eatten without problem (until now).

so my question is this,
Can a snake be blinded by double retained eye caps?
also,
Can a BP become acustomed to low humidity?

When I first got her she came from a house where she had no humidity( hardly ever had water even) and I keep her tank 55 - 60% most always.