What is the function of the optic nerves present inside our eyes?

• In human eyes, the lens focuses light on the back of the eye, on a layer called the retina. The image of the objects is formed on the retina. 
• It contains several nerve cells that are sensitive to light and colours. Sensations felt by these nerve cells in the retina are then transmitted to the brain through the optic nerve.

Therefore, we can conclude that the function of the optic nerves is sending signals to the brain.