I had my appointment this morning and it's a cataract that is causing the drastic change in my left eye's prescription. Aging, long-term exposure to sunlight, smoking... yes yes yes... I tick those boxes. In any event, I went ahead and ordered glasses with the current prescription and will address the cataract next winter when I'm not mowing. My optometrist advised that I will need a different correction at that time with or without the surgery. I won't be ordering a spare Zinni set of glasses for six months use.