It makes no sense to pay an optometrist for things like precisely-made lenses and glaucoma checks when most those things could be taken care of by getting some novelty frames, index cards, and thumb tacks.
I am going to go out on a limb and assume that some of the people reading the site, and these words, are gigantic dorks. These people will have the usual dork detritus including massive eyeglasses they use to help them from getting killed by uncovered manholes or city buses.
As anyone knows, getting glasses is a hassle. First there's the usual talk where the optometrist asks what percentage of a patient's waking hours are spent in front of a computer and frowns when the answer is "all of them" (like that's unheard of in an era in which even shoes come with TV screens). Then there's the part when the optometrist squirts concentrated hydrochloric acid  directly onto the patient's eyeballs in order to give them huge stoned-looking eyes for the rest of the day, because optometrists think that's funny. They award themselves ten points if the patient is searched for illegal drugs shortly after leaving the office.
And then, inevitably, there's the part where the optometrist tells the patient how much blinder they've gotten in the past year, and sells them a pair of glasses that will keep them from breaking their own nose with their hand the next time they try to read their wrist watch. Those glasses cost a pretty penny.
Well, not anymore.
Some readers will have noticed that when they look through a pinhole at objects around them, even if they have terrible vision, those objects will be perfectly clear.
Light bounces off objects in tons of different directions. These bits of light hit everywhere on the eyeball. The front of the eye is a curved lens which bends the light inward, focusing it tight on the retina in the back. At least, when people are kids it does. For most people, as they get older, the lens of their eye gets sloppy, not as flexible. Its metaphorical belly bulges over the equally metaphorical waistline of its especially metaphorical jeans, and the tight focus of light becomes a messy smear.
The pinhole slims down the light. It lets only a narrow band of it through, and a narrow band of light coming in allows for only a narrow strip of light to hit the back of the eye. The result is, the image is in focus.
To focus on something in a pinch, all that needs to be done is to use a thumbtack, needle, or paper-clip to punch holes into a strip of paper or fabric. If holding that paper in front of the eye all the time is tiring, set the paper into a frame. Say, this stylish little number:
There are pinhole glasses, which take advantage of this property to correct vision, but there are problems with them. For one thing, the light getting in isn't just narrow, it's dim. So wandering around with pinhole glasses will be like walking through constant dusk.
This writer has suggested skipping the middle-man and just sticking thumbtacks directly into the eyeball, but no optometrists have replied as of yet.