Originally Posted by Michele
I had to put mine all the way up to read in the dark. Customer service didn't say anything about the recommended levels when I asked them. Just silence.
What they would probably recommend is what the PW tells you when you bring up the light adjustment: 0-5 for dark rooms, 20-24 for bright rooms, in between for in between rooms (in full sun you might as well turn it all the way down). But nobody can really tell you what is going to work best for you.
I usually set it at 0-1 so I can retain some night vision, in case I need to get up and move around said dark room. But it is not suitable for long reading sessions. Reading books by candlelight was never superior to reading with daylight, and this is no different. You are asking your eyes to work a lot harder.
Another trick is to enlarge the type size and put it in landscape orientation. This makes it a little easier on the eyes while retaining good justification of the text. Seems to be a little easier to hold that way, also.
I can understand why you might prefer to turn it all the way up (makes it easier for eyes to focus when there's more light coming into your eyes, causing your irises to contract—pinhole effect etc.) but at that point it is probably no different physiologically than reading a backlit screen in terms of messing up sleep cycles. And let's face it: if you are reading in the dark, your sleep cycles are probably already messed up!