The lateral sulcus separates the frontal lobe from the temporal lobe. The frontal lobe can be divided into a lateral, polar, orbital (above the orbit; also called basal or ventral), and medial part. Each of these parts consists of a particular gyrus: 1  Lateral part: lateral part of the superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus. 2  Polar part: Transverse frontopolar gyri, frontomarginal gyrus. 3  Orbital part: Lateral orbital gyrus, anterior orbital gyrus, posterior orbital gyrus, medial orbital gyrus, gyrus rectus.
Less common causes of glaucoma include a blunt or chemical injury to the eye, severe eye infection, blockage of blood vessels in the eye, inflammatory conditions of the eye, and occasionally eye surgery to correct another condition.
Topic Overview. All forms of glaucoma cause the same characteristic changes in the optic nerve, at the back of the eye, and the nerve fibers. Glaucoma causes changes in the appearance of the optic disc (notching or thinning of the edge) and changes in the nerve fiber layer (fiber defects). Moderate glaucoma refers to optic nerve damage with moderate loss of vision in at least one eye. 2  But sight in the center of the eye (central vision) is not affected. 3  Severe glaucoma refers to optic nerve damage with loss of vision in both eyes or loss of sight in one eye that includes central vision loss.