It’s hard to believe that something so small like the human eyeball can have so many parts all working together to give us the ability to see. It’s sometimes regretful that we don’t take enough care of our eye even though we depend on it for so many of our day to day activities. Imagine if we just take the time to understand what makes it tick, maybe this interest may be able to save our eyes in the near future.
Among the many parts of the eye, the optic nerve has a very significant responsibility. As you know, light passes through the eyes and it’s other parts to get to the retina where it will be converted as electrical impulses. These electric impulses then reach the optic nerve whose responsibility it is to relay them to the brain. You might liken the optic nerve with a cable that connects the retina to the brain and what passes through them are the electrical impulses that the brain perceives as images.
The front surface of the optic nerve that is connected to the retina is called the optic disc or optic nerve head. Since there are no photoreceptors in this area, this part of the retina cannot respond to light stimulation, thus unable to receive and transmit electric impulses. This part of the eye is what is commonly referred to as the “blind spot”.
After leaving the back of the eye, the optic nerve travels to the optic chiasm in the brain. From here, the nerve fibers from the optic nerve branch out and half of them cross over to the other side. The nerve fibers that have crossed over become called the optic tract, then to the optic radiation until they reach the visual cortex of the brain. The visual cortex ultimately translates the electrical impulses as visual images.
By the very nature of the anatomical structure of the optic nerve, doctors can often determine which part of the optic pathway is damaged based on the patterns of vision loss.