Some people are very near sighted. I am not sure that this necessarily means they are not far sighted too. But if you can focus much closer than about 10 inches (the 'least distance of distinct vision' according to the field of optometry), then you are on the nearsighted part of the spectrum. We sometimes have customers that can focus at 4" ! Such people can see inclusions with their naked eye that the vast majority of us cannot.
Most younger people <late 30s will be able to focus reasonably close until they become presbyopic, and lose the natural focusing ability due to a stiffer lens. If you are long sighted this process happens sooner, but I'd expect a young low hypermetrope (long sighted of +2 dioptres) or so, still be able to manage focus within 7 inches if they really went for it. Myopes retain the ability to see at short focal range even after presbyopia sets in, without reading glasses.