My eyesight is -4.00/+050/105 in the right eye and -4.50/+075/70 in the left eye. I have three related questions.
1. For my main pair of glasses, is the 1.67 the best option? Or is the 1.61 just as good? The cost difference is not monumental but if it won't make a difference in appearance (i.e., not noticeably thinner) or my ability to see, then I'm not sure I see the point in spending more on top of what is likely already going to be a $350+ purchase. This is the pair where I'll spend what is necessary because I wear them all the time. If a 1.67 is best, if there will be a noticeable difference, then that's fine, I'm just wondering because it seems like they tell you that regardless of prescription strength.
2. For my second pair of glasses, a backup pair, and sunglasses, is the 1.61 okay? This might already be answered depending on the first question answer. I won't be wearing these often, the second not much at all, the sunglasses maybe twice a week during the summer. Not looking to spend hundreds on these and going down to 1.61 can be a good way to keep things more reasonable from the prices I've seen.
3. Finally, is it a problem to go from 1.67 glasses to something like a 1.61 sunglasses some of the time? For instance, wearing the main pair for most of the day and the 1.61 for 2 hours when I drive somewhere. Is it detrimental to my eyesight in some way or is it no big deal?
I'm trying to save money where I can but I'm used to spending on the first pair. The backup glasses and sunglasses I've avoided because of expense, but plan on getting those online at affordable prices, just want to make sure there isn't a problem with switching between. I don't need help making my eyes worse.