....... HOME ....... MAIN ARTICLE VERSION 5 ... HISTORY ... DISCUSSION .... GALERY .... EDIT V 5 Contents Introduction * Types Of Glaucoma ....- Open Angle Glaucoma ....- Narrow Angle Glaucoma * Tests For Glaucoma * Treatments For Glaucoma Keywords See Also References Bibliography GLAUCOMA Disease Of The Eye Ophthalmology Old Version - 5, updated Mon, Apr 10, 2017 at 17:30:12, 4454 bytes - by relopez. This article is for information and educational purposes only and is not intended to give medical, legal or professional advice. Glaucoma is damage to the optic nerve caused by high pressure of the liquid, the aqueous humor, inside the eye. INTRODUCTION Because the eye is a hollow organ, it needs fluid under pressure in order to maintain its form. The name of this fluid is vitreous humor and its pressure is controlled by maintaining the rate of fluid production and fluid outflow within certain parameters. Fluid is produced by the ciliary body which is behind the iris and then flows out of a ring shaped tissue called the trabecular network located between the iris and the cornea. There are different ways that the functioning of the trabecular network can be impaired. This causes a rise in intraocular pressure (IOP) which leads to mechanical damage to the optic nerve. Normal IOP is considered to be 10 to 21 mmH2O. Treatment begins when the IOP reaches between 25 to 30. A pressure of 30 will cause measurable damage to the optic nerve in one year in half of those who have that pressure. The loss of vision in early glaucoma is in the mid periphery. Because it only affects central vision late in its course, it is basically impossible to notice early glaucoma. Because of this it is important that people over the age of 65 have yearly eye exams. TYPES OF GLAUCOMA Open Angle Glaucoma This is the most common type of glaucoma. Open angle glaucoma is caused by a loss of function of the trabecular meshwork. Risk factor are age and a familial predisposition. Having relatives with glaucoma increase the risk of getting glaucoma. The name open angle glaucoma refers to how open the angle is. The angle refers to the amount of space between the iris and the cornea. When the angle is very narrow this means that the iris is almost touching the cornea and is at risk for blocking the trabecular meshwork and causing a glaucoma attack. That type of glaucoma is called primary open angle glaucoma. However, the name open angle glaucoma is a little misleading because it does not mean that the angle is actually open. All it means is that the high pressure is not caused by an obstruction of the trabecula by the iris. A persona can have both types of glaucoma. He can have open angle glaucoma and narrow angles at the same time. Open angle glaucoma is usually treated by medicated drops in the United States. When the use of multiple drops is not sufficient then various types of surgery may be performed. The rise in pressure is usually very gradual and sometimes does not reach very high levels. However, even somewhat elevated IOP can cause gradual loss of vision which is irreversible. This level of pressure does not cause pain and it is difficult to detect early loss of vision from glaucoma. Because of this it is important form persons over 65 to have yearly screening eye exams. Narrow Angle Glaucoma This is a rise in pressure in the eye which often occurs suddenly and is caused by a physical obstruction of the trabecular meshwork by the iris. The pressure can rise over the course of several hours and can reach very high levels which can put the eye at immediate risk for permanent loss of vision. A person who suspect that he/her is having a narrow angle glaucoma attack needs to seek immediate medical attention at an emergency room who has an ophthalmologist on call. People who are far sighted (who have positive prescriptions, those which make the eyes look larger) are at greater risk for glaucoma attacks because their eyes are smaller than average and the iris and the lens is crowded within a smaller space. A screening eye exam can detect narrow angles before an attack occurs and a simple laser treatment called a peripheral iridectomy (PI) greatly reduces the risk of a future attack. A PI is a small hole in the iris, usually made by a laser. If an attack occurs the pressure will be lowered using medicated eye drops and sometimes by the use of oral diuretics to lower the IOP. When the IOP is very high the cornea becomes cloudy and the iris touches the cornea which make giving laser treatment impossible. Once the IOP is lowered and the attack is broken a laser PI can then be performed. However, it is sometimes impossible to break the attack and the PI must be performed in the operating room by means of surgery. TESTS FOR GLAUCOMA TREATMENTS FOR GLAUCOMA KEYWORDS The following keywords are alternate terms which can be used to access this page. glaucoma SEE ALSO REFERENCES BIBLIOGRAPHY top