I was born with cataracts and had the natural lenses in my eyes removed when I was days old. Fast forward to 2018 and I had intraocular lens implants (I believe it's called) under general anaesthetic. Went fine for the most part, however I had to go to A&E because the pressure in one of my eyes was ~65. The cause was blood leaking into the back of one of my eyes (if I remember correctly), and they had to use the drops you mentioned. At the time I was a bit concerned with what they were going to do, but obviously was willing to have whatever done to get back to normal.

I'm still impressed by how well those drops worked. And, yeah. All I could see was red (blood), and all I felt was just a prick of something sharp. Was done within probably 10-15 minutes.