(1) if blocking blue light is going to make a difference, how quickly should I see it?
For me the difference was immediate. But, that's because I'm typically staring into my computer screen late at night. Honestly, staring at a computer screen is probably the worse thing you can do at night (again, it's like staring at the sun) and for years I thought I was somehow special that I never got tired. Little did I know I was frying my pineal gland.
So, the day I installed f.lux on my computer, I noticed a difference. But when I got the cheap amber glasses I really noticed a difference. I felt extremely tired after putting them on, when I normally could stay awake if I wasn't wearing them. But, again, they aren't magic. I would have had the exact same effect if I were camping by fire-light or sitting in a dark room. My dreams became more vivid with the glasses (this was before I ever took RS).
what should I be doing? Going to bed once it's too dark to see by normal light and using an orange-filtered torch to light my way in the bathroom (no windows) and if I have to get up in the night?
Ideally, everyone should be getting 9+ hours of melatonin production
on a consistent schedule. The more consistent your daily schedule, the more your body will learn to produce it's own melatonin on que. According to studies, it's the changing of schedule that messes with the circadian rhythm and dampens melatonin production.
So...for the average person, count back 9 hours from when you want to get up. If you want to get up at 7:00 AM each morning, then you only need to wear the glasses on nights that you are up past 10PM. If you're always in bed with the lights out by 10PM, there's no need to wear the glasses. If you want extra hours of melatonin, you can put the glasses on earlier — as some people say wearing them an hour before bed makes it easier to fall asleep. However, if you do that, you'll want to
always do that on that schedule so that your body clock is on a consistent schedule.
The important thing to remember is that
consistency of the timing is how you improve your melatonin production. Your body clock isn't really engineered to deviate by its schedule by more than 15 minutes (the sun usually only changes its schedule by about 5 minutes per day, depending on where you live).
However, there's no need to be obsessive about it. Your body clock will not get deviated from one or two days of not wearing your glasses. But, the research suggests that after the third day of inconsistency, your body clock will get confused and forget its internal schedule. Interestingly, a the moon is it's brightest for about 3 days — though, it's intensity is never greater than 1 lux (while your living room is about 50 lux).
The amber "low blue" nightlights are excellent. Lowbluelights.com makes a little LED torch that attaches right to the top of any 9-volt battery.
If I end up having to get prescription blue-blocker specs, how can I be sure that my optician is using lenses that will really block the correct wavelengths? What should I be asking for?
They do make "fit-over" eyewear in the States. Not sure if that's what was slipping off your face but they literally fit over your prescription glasses:
https://www.lowbluelights.com/products.asp?cid=18
