Needles are hard to thread, if you've got no binocular vision (like me). In fact, they're friggin' impossible.
(I have a hell's brew of retinopathy (it's dormant, but I've only got half the visual field in my right eye), a fovea in the left eye that's held in place by a clip (say goodbye to fine detail!), myopia, astigmatism, and now a forty-something's presbyopia. My vision for close-up detail work is terrible, I have to rely on paralax for judging distances when driving (guess who doesn't drive at night?) and threading a needle has been impossible for me since I was 25. Even the diamond-wire needle threaders barely help. This is the first thing I've seen that might actually work!)
Actually binocular vision doesn't help - I almost always close one eye when threading needles. I need to wear reading glasses now though, getting too old to see small stuff clearly enough. (I cheat - I got some extra strong reading glasses for close work like threading needles and removing splinters (3 diopter, normally use 1.0 to 1.5 for reading) - they are a big help.)
(I have a hell's brew of retinopathy (it's dormant, but I've only got half the visual field in my right eye), a fovea in the left eye that's held in place by a clip (say goodbye to fine detail!), myopia, astigmatism, and now a forty-something's presbyopia. My vision for close-up detail work is terrible, I have to rely on paralax for judging distances when driving (guess who doesn't drive at night?) and threading a needle has been impossible for me since I was 25. Even the diamond-wire needle threaders barely help. This is the first thing I've seen that might actually work!)