Final answer:
Jewellers and others doing detailed close-up work have a greater ability to see objects at a closer range than the standard 25 cm due to the accommodation of their eyes.
Step-by-step explanation:
People who do very detailed work close up, such as jewellers, can often see objects clearly at a much closer distance than the normal 25 cm due to the accommodation of the eye. This is a process where the lens changes its shape to increase its power, allowing the eye to focus on close objects. This change is controlled by the ciliary muscles which alter the curvature of the lens. A normal eye can see from 25 cm to infinity, but through accommodation, the focal length of the lens is shortened to focus on objects much closer to the eye. Jewelers, due to their profession, might have trained their accommodation ability to be more effective at shorter distances.