Refractive errors in the eye
This is called myopia (nearsighted). If you move the object closer, (for example, your spouse comes to you for a hug), the image focus moves towards the retina and your spouse comes into focus.
If the eye is too short or the cornea is too flat, the image focus lies behind the retina and the image is blurry. This is called hyperopia (farsighted). Sadly for hyperopes, no matter where your spouse is, they are never in focus.
If the cornea is round and symmetric like a basketball, the cornea has NO astigmatism. If it is shaped like a football, (with one axis flat and the other steep), that cornea has astigmatism. Like hyperopia, astigmatism makes your spouse blurry no
matter where they are. Of course, glasses, contact lenses, refractive surgery and cataract surgery can all bring your spouse into perfect focus!