Final answer:
The human eye generally achieves full globe size by adolescence. The power of the eye to accommodate changes later in life, due to stiffening of the lens, particularly affecting the ability to focus on close objects with age.
Step-by-step explanation:
At What Age Does the Eye Achieve Full Globe Size?
The human eye typically achieves its full globe size during adolescence. While the power of the eye to accommodate (adjust focus) varies during one's life, the physical growth of the eyeball itself generally reaches completion by the early teenage years. After this point, changes in the eye are usually related to the lens and its ability to accommodate, not to changes in the overall size of the eye globe. For instance, as people age, the lens may stiffen, leading to a condition known as presbyopia, or elder eye, which affects the ability to focus on close objects.
For an eye with a typical 2.00 cm lens-to-retina distance, the power of the eye ranges from 50.0 D for distant vision to 54.0 D for close vision when fully accommodated, representing an 8% increase in power for close vision. This reflects the eye's need to be more converging when viewing objects at a close range. Older individuals, usually by about 40 years old, have a normal 8% ability to accommodate, whereas younger individuals tend to have a greater ability to accommodate. As we age, the lens stiffens, leading to reduced accommodation ability.