optic nerve

Glaucoma is the term used for a group of eye disorders involving gradual and permanent damage to the optic nerve. Usually, this damage to the optic nerve occurs because fluid pressure within the eye (intraocular pressure) is too high; however, damage may also occur as the result of an insufficient blood supply to the optic nerve. Since the optic nerve is responsible for transmitting images from the eye's light-sensitive retina to the visual cortex of the brain, damage to the optic nerve can have serious effects on vision. In the initial stages of glaucoma, people tend to lose peripheral (side) vision; though, central vision is affected as the damage to the optic nerve progresses. NOTE: Most types of glaucoma develop slowly and subtly over time without dramatic or painful symptoms.
There are several types of glaucoma. Even though the most common type of glaucoma cannot be cured, usually if detected and treated in the initial stages, it can be controlled to preserve vision. Since glaucoma tends to develop gradually without noticeable symptoms yet causes permanent vision loss before awareness by the patient, early detection is challenging and very important. Once diagnosed, it is essential that patients dutifully comply with treatment programs prescribed by a physician or blindness can result.