Fair warning: This is long, but the subject is important and deserves serious treatment wherever it's found.
Before proponents of negative eugenics start with more of the same nonsense about how other people - for rarely do they say this of themselves basically have no right to live, they need a lesson in perspective.
Our species has existed as such for about 200 000 350 000 years (and, as the link suggests, we've spent much of that time in violent conflict with each other and potentially with genetic near-cousins).
In terms of geological time, we're barely here right now. This is a fact that should encourage humility, not hubris.
And at no time in our existence, to the best of my knowledge, has our species come close to being an apex predator.
To give readers a better perspective on our place in the food chain, it's instructive to see where our naturally soft, clawless bodies (which lack even the advantage of continually growing teeth such as rats have) actually fall when compared to other predatory species.
The Smithsonian published an article about where we - and this includes all human beings, everywhere - actually rank in the food chain:
We’re not at the top, but towards the middle, at a level similar to pigs and anchovies
We have, since the development of our species, been finding ways to compensate for our weaknesses (e.g., firearms). Human beings do it collectively, and individuals with disabilities do likewise either with some help or alone.
History has recorded how people with intellectual and physical disabilities not only worked, but the lucky ones found a niche where the particulars of disability worked to their advantage.
Examples include people with certain intellectual disabilities who can work, and work hard. For quite a few in that category, repetitive work is a preference: Once they learn how to carry out their duties, they can perform as well as anyone else (if not better, for those who find comfort in repetition). They could do very necessary but commonly undesirable jobs such as street cleaning; they carted off tonnes of horse manure and urban garbage. They worked as lamp-lighters.
Another example is in the choice of who both Roman and medieval builders hired to operate 'the treadmill crane' - a dangerous, manpowered wooden wheel located dozens of meters above the ground and used for lifting or lowering stonework. The men who walked those wheels were often blind.
"Tender eyed" persons (e.g., Leah in Genesis 29:17) were mentioned even in the Bible, and Paul indicates having developed a serious visual impairment of his own later in life (Galatians 6:11). Ancient near-Eastern cultures was not exactly famed for kindness toward the disabled, many of whom were barred from participating in public religious events. Infertile women were especially ostracised. And yet, in part because of Israelite charity (such as the permission to glean fields
and gleaning was by no means easy work) there they were still living and sometimes thriving.
More interesting right now is that many human jobs are being done better, faster, and free of error by machines. Our finest minds even use them to augment the theoretical models and scenarios we build to better our technology and increase our knowledge. People working around dangerous machinery the very people whose jobs are now being outsourced to the machinery itself are generally fit and free of obvious disability. (But I know one man who develops and maintains process control software mastery over the machinery who cannot walk and who breathes with mechanical assistance.)
I can't help but to think of what went wrong as the concept of eugenics went mainstream - decades before Rosalind Franklin and that new breed of researcher could study the physical structure of DNA, there were already people using a very incomplete understanding of heredity to excuse everything from forced sterilisation to mass murder.
In light of such facts, it is nothing more than self-serving hubris for any one person to make blanket statements about who else should live and die.
This OP is especially risible: I've found many people with glasses don't need them for daily living but rather for close or distant work (such as computer work or driving). In the past, as the lens became less flexible with age, people merely accepted fuzzy sight at some distances as one of the ways time fucks us all.
Now we use a simple adaptation: Glasses.
My point should be clear: We, human beings, have never been anywhere near the top of the food chain. No - something happened to our species, with its opposable thumbs and cerebral cortices, that permitted us to explore architecture, art, culture, medicine, and even space travel despite our physical weaknesses when compared to other species.
It's wrong for me to say this, I guess, but I hope arrogant persons who spend time judging others' alleged fitness to live (and based not on actions but on innocent conditions of being) will one day find themselves in the same position: It is, for some assholes, the only way they come to recognise that, yes, that person in the wheelchair is as capable of joie de vivre, and quite possibly just as gainfully employed, as everyone around him. He certainly has the same right to live. (And while I support legal euthanasia, this kind of discussion is part of why it's so vitally important that high value be placed on life as a matter of course. That should be taught from the cradle and if we are to survive the many dangers associated with growing through our technological adolescence, we'd better start damned soon.)
I support the use of lifelong financial incentives offered against having biological children to people who could pass on devastating genetic disorders. If they selflessly choose to forgo the only form of 'immortality' some people believe in, they should be offered a comfortable situation and for those with the desire and ability encouraged to adopt kids who are already here.
I don't support such a policy in the belief people with disabilities are somehow less worthy to reproduce but rather because I’ve seen the absolutely brutal, painful, and lifelong cost to some disabled people effected all their lives, in nearly every arena, in some cases because a single part of the genome failed. (This is just one of so many reasons why the idiot OP's view of glasses as disability is so fucking ridiculous.)
I do think positive eugenics encouraging people with highly useful traits to reproduce within reason can and should be encouraged, but in such a way that never, ever loses sight of the fundamental right to life that should be protected for everyone. With our growing scientific understanding, we must ensure that our ethical concepts keep pace with our discoveries else we could become a monstrous species more dangerous than we already are. Or we could wipe ourselves out completely.
Always. Always. We must always be careful to ensure that our efforts to limit human suffering do not end up doing more harm than good; that we do not treat people with disabilities as less than human (and nor may we spoil those with favoured traits; they should recognise their inborn advantages are not evidence they are somehow better than others and thus more worthy to live).
It may be apocryphal, but the following quote has been attributed to the abolitionist and former slave Sojourner Truth. It is a contested piece of transcription from a speech she delivered in 1851:
Then they talk about this thing in the head; what's this they call it? [member of audience whispers, intellect’] That's it, honey. What's that got to do with women's rights or negroes' rights? If my cup won't hold but a pint, and yours holds a quart, wouldn't you be mean not to let me have my little half measure full?
The sentiment is a true one, in my opinion. There is something cruel and exceptionally self-serving in the arguments of individuals who conclude they should be able to place artificial limits on the potential of other people merely because those other people may (or may not) have actual limits (be they physical, intellectual, emotional, financial, educational, and so on).
This was my soap box. Wherever I find shit like the OP, you'll find me here.