Accessibility for the visually disabled sucks
I am involved with a group of partially-sighted and blind people and have the following observations:
1) Almost all use iPhones as the built in screen reader and accessibility options that can be turned on are very very good. Not quite excellent, but part of the problem is poorly designed Apps - I'll come back to that. Several have iWatches too, and find them very useful.
2) Not quite so many use iPads - again, the built in accessibility is good. There is some Android use.
3) On windows PCs, the JAWS screen reader is pretty good, so long as it 'knows' about the application is is reading the screen for.
JAWS + Web browser is a variable quantity, depending highly on how the websites have been coded.
4) Websites - many websites are *TERRIBLE*. Often accessibility is not thought of, so you end up with unlabelled fields, or all having the same fieldname. No thought is given for navigation by screen-reader, so even if the fields and buttons are labelled, you have to laboriously move through the entire head-of-page and/or left-hand menu to get to the text that is different and/or useful on any particular page. Many sites have obviously never been tested for accessibility.
5) Apps on smartphones - some are good, some have the same failings as websites - it doesn't matter how good the built in accessibility functions are if the app doesn't expose itself to them.
There are screen magnifiers for the partially-sighted, and those unable to discern text on a screen can use screen readers, or braille displays (which are breathtakingly expensive, and often not supported). Most helping aids are designed around use of Microsoft Windows - in my unrepresentative sample, few used Macs, and none used Linux. It is possible to used Linux from a Braille display - the reasonably well-known Knoppix distribution takes care to support them (Knoppix ADRIANE) because the maintainer's wife is visually disabled - there are other distributions that aim to offer similar capabilities e.g. Talking Arch Linux. There is also emacspeak. My impression is that while there are some dedicated, enthusiastic, and technically accomplished visually-disabled users of Linux, it is not a mainstream choice.
I suspect most visually disabled people who have a job are forced into using Windows as that is what most businesses use. So even if an Apple Mac has better accessibility it may not have access to the applications used in a business. I know this to be a problem for many - and many business-oriented applications have very poor accessibility. Sometimes it is so bad, a visually disabled worker needs a secretary to operate necessary business applications, which is something very, very, few companies are willing or able to justify.
The problem is that if visually disabled people find it more and more difficult to access modern IT applications, websites and apps, they will become further marginalized and reliant on sighted helpers. While most people think it won't happen to them, age-related visual disability is a real problem - cataracts are usually operable, but age-related macular degeneration, diabetic retinopathy, and glaucoma increase in likelihood as you age, so making sure that people with visual disabilities are not left behind by IT is really a form of insurance for yourself. Making the necessary adjustments and learning new ways of doing things often gets more difficult with age, so it is a good idea to make things as simple as possible - which is hard work.
IT really ought to be an enabler, but too often it is a barrier.