I would think the blurriness is caused by the cataracts. Regarding cataract surgery, you may want to get a second opinion. See this link:
http://www.amd.org/our-newsletter/148-cataract.html
Regarding the sewing machine needle, there are "easy thread" types that have an opening on the side. You slide the thread down the side of the needle until it slides into the opening. I couldn't find a link, but I know my 97yo mil has this type of needle in her machine.
For hand sewing, these needles are easier to thread:
http://www.spiraleyeneedles.com/About.html