Final answer:
The term for objects arranged off-center causing an aberrated image in an imaging system is called a coma, leading to a pear-shaped image. It is one example of optical aberrations, which also include spherical aberration and astigmatism in vision correction lenses.
Step-by-step explanation:
When objects in an imaging system are arranged off-center, it causes a type of optical aberration known as coma. This phenomenon results in an image that often appears pear-shaped, since the rays of light from the object do not converge at a common focal point, as they are not all originating from points on the optical axis. Coma can be particularly problematic in various systems where precision optics are key, such as telescopes, microscopes, and cameras.
Another common optical aberration is spherical aberration, where rays from the edges of a lens focus at a different point than rays closer to the axis, causing a blurred image. Systems used for vision correction, like eyeglasses and contact lenses, can also suffer from similar issues like astigmatism, which affect the clearness of vision.