Those of you thinking about purchasing the Varia Vision should consider this...I have a mild case of nearsightedness (-1.75 in both eyes). The VV is very readable to me although not crisp. However, my son, daughter and wife cannot focus well on it as their nearsightedness is worse (don't remember their numbers at the moment). They find the text blurry. There is no focus adjustment (diopter) available.
This may seem contrary to the definition of nearsightedness; meaning you should be able to clearly see objects up close but not at a distance. But I believe that the lens of the VV "tricks" the eyes as if you were seeing a screen at a distance. To me, it's like watching my 40" LCD TV at 12 feet. I actually did this by varying the distance between myself and the TV until what I saw in the VV just covered the frame of the TV and then measured how far I was away.
If possible, try before you buy.
Edit: With -1.75 in both eyes, I cannot focus on the tiny temperature/time readings that are centered and are on top of every data page. The data page metrics are fine due to thier larger font size.