People with low vision use a range of strategies and tools online, including browser and operating-system zoom, dedicated screen magnifier software, high-contrast or dark display modes, and customized text sizing, often in combination. This is why WCAG requires that text can be resized up to 200% and that layouts reflow cleanly at high zoom, rather than assuming a fixed, small viewing size.
Low vision is far more common than total blindness; the World Health Organization estimates it affects hundreds of millions of people worldwide, which makes it one of the highest-impact groups for basic accessibility practices like sufficient contrast and resizable text.