Final answer:
The size of the optic disc is approximately 1.7 mm in diameter. It is important to note the size of the disc as changes in size can indicate eye conditions.
Step-by-step explanation:
The size of the optic disc is approximately 1.7 mm in diameter. The optic disc is the area where the optic nerve connects to the retina and is responsible for transmitting visual information to the brain. It is important to note the size of the disc because any abnormalities or changes in its size can indicate underlying eye conditions, such as glaucoma or optic nerve swelling.