I was just going in for a routine eye exam to update my prescription. The guy said, "The good news is that we can skip the rest of the exam." The bad news is that I had cataracts.

The same thing happens with people with glaucoma, or macular degeneration, or...

Being able to see is a really big deal. Catching stuff that can make you blind rather abruptly is a big deal. On the other hand, as you say, being able to afford to get a prescription and glasses that fit them is also a big deal.