The calcarine, also called the calcarine fissure, is located on the surface of the brain near the bottom. This particular part of the brain is actually considered an anatomical marker or landmark. The visual center of the brain is located near the rear of this fissure and controls most aspects of how a person sees. The area which controls peripheral vision in located at the front of the fissure, making the entire area fairly important.
This part of the brain is located very near the occipital pole where two blood vessels meet. It extends to a certain point below the splenium of the corpus callosum; then it is joined by the the parieto occipital sulcus. When a diagram of the brain is examined, the calcarine appears as a pathway into the brain. This is not entirely true, as the fissure does not actually go all the way through the brain.
When damage is done to this area of the brain, it can affect eyesight in many different ways. It can blur the vision, distort distances and even cause blindness in some cases. This could result from a frontal head injury obtained by accidents such as vehicle collisions, falls, or chemical poisoning such as radiation. Most often, damage done to the calcarine cannot be repaired. Luckily, due to its location near the bottom portion of the brain, it takes an extreme amount of external trauma to affect the fissure directly.
Studies have shown that the magnetic resonance (MR) of the calcarine fissure changes due the effects of retinal degeneration. This may show that not only can damage to this part of the brain affect vision, but damage to vision can affect this part of the brain. It may also be interesting to note that mental imagery causes the occipital lobe area of the brain to react, but causes no reaction in the calcarine. Many scientists have stated that these studies prove that the calcarine deals only in external visual stimuli, even though other parts of the brain recognize internal images.
While many advances have been made in science and medical fields, and more of the calcarine fissure is understood, it is still a vastly mysterious region of the brain. Studies continue to show new data about the fissure, answering some questions, but perhaps creating even more. More studies also aid doctors and scientists in discovering the root causes of some visual impairments and how to effectively treat them.