There are many types of Glaucoma. However, there are two main types of Glaucoma: Primary Open Angle Glaucoma (POAG), and Angle Closure Glaucoma. Sometimes it is possible to have damage to the optic nerve, even with a “normal” Intraocular Pressure (IOP). When optic nerve damage has occurred despite a normal IOP, this is called Normal Tension Glaucoma. Secondary Glaucoma refers to any case in which another disease causes or contributes to increased eye pressure, resulting in optic nerve damage and vision loss. Since Primary Open Angle Glaucoma and Angle Closure Glaucoma are the most common, we will limit our discussion to these types of Glaucoma.
Primary Open Angle Glaucoma
The most common type of Glaucoma is Primary Open Angle Glaucoma (POAG). In the “normal” eye, there is a continuous production and drainage of a clear colorless fluid called “Aqueous Humor”. This production and drainage is balanced so that an equal amount is produced and drained in order to maintain an equilibrium resulting in a “normal’ Intraocular Pressure (IOP). Patients with Primary Open Angle Glaucoma usually have an increase in Intraocular Pressure (IOP) upon routine measurement, called Tonometry.
In the event that there is either too much Aqueous Humor being produced or too little Aqueous Humor is being drained, there is a rise in pressure inside the eye. Any elevation of Intraocular Pressure (IOP) is considered “abnormal. This elevation in pressure (IOP) causes the circulation in the optic nerve to become compromised, depriving it of oxygen and nutrients, resulting in permanent changes and even damage to the optic nerve. Any damage to the optic nerve can result in a loss of vision. The optic nerve is the connection responsible for communicating visual images between the retina and the brain. When the optic nerve is damaged, it is not able to carry visual images, resulting in vision loss. This is why it is so important to monitor, detect and control Intraocular Pressure (IOP). If left untreated, an elevated Intraocular Pressure (IOP) may, over time, cause slow, progressive and permanent damage to the optic nerve that can result in blindness. This is the nature of Primary Open Angle Glaucoma.
Angle Closure Glaucoma
Angle Closure Glaucoma can be divided in two main types: Primary Angle Closure Glaucoma and Acute Angle Closure Glaucoma. Although Angle Closure Glaucoma occurs much less frequently than Open Angle Glaucoma, it is important to understand it because it has the ability to produce considerable vision loss in a short period of time.
Primary Angle Closure Glaucoma accounts for approximately 10% of all cases of Glaucoma and about 2/3 of these once again produce no symptoms for patients.
Acute Angle Closure Glaucoma is one of the only types of Glaucoma that produce distinct symptoms that include pain, light sensitivity, redness, blurred vision, colored haloes around lights and nausea or vomiting.
Angle Closure Glaucoma is characterized by a blockage or complete closure of the drainage structure of the eye called the Trabecular Meshwork. The Trabecular Meshwork is actually a fine filter. If it is blocked or obstructed by any alteration in the size or shape of the surrounding structures, or by change in the size or shape of the tissue itself, it will cause the Intraocular Pressure to elevate. In instances where the meshwork becomes blocked abruptly, it will cause a sudden rise in the Intraocular Pressure (IOP), resulting in Acute Angle Closure Glaucoma. Acute Angle Closure Glaucoma is characterized by this sudden rise in pressure which will can cause pain, redness, light sensitivity, colored haloes around lights, nausea or vomiting and blurred vision, and if left untreated permanent loss of vision.
Acute Angle Closure Glaucoma is therefore considered a medical emergency. If you experience a sudden onset of pain, redness, blurred vision, light sensitivity, haloes around lights, nausea and vomiting, please call The Eye Center at 303-777-5455 and relay these symptoms to the receptionist so that you can be given an appointment immediately.
While there can be several causes of Angle Closure Glaucoma, it is most often caused by anatomical changes within the internal structures of the eye. Angle Closure Glaucoma is considerably more common in farsighted eyes, which tend to be smaller and in patients between the ages of 45-60 years of age where the Crystalline Lens is beginning to swell.
During your routine eye exam if one of the eye doctors observes or measures a narrowed angle, he or she will perform an additional examination procedure called Gonioscopy. This will allow the doctor to directly examine the Trabecular Meshwork and the angle in order to carefully assess your predisposition to Angle Closure Glaucoma. By placing a special contact lens on your eye and then using the slit lamp biomicroscope to fully examine the meshwork and the angle with Gonioscopy the doctor will be able to make a thorough evaluation.
In the event that you are at risk for Angle Closure Glaucoma or in the event that you have Acute Angle Closure Glaucoma the doctor may initially prescribe some medication to begin to lower the pressure. Also, he or she will most likely recommend performing a type of Glaucoma Laser procedure in order to produce a small opening or hole in the Iris so that Aqueous Humor can drain from the eye more effectively. This procedure, called a “Laser Iridotomy”, is quite successful in treating Angle Closure Glaucoma and preventing recurrences
Glaucoma is a very complex eye disease, and not simply an elevated Intraocular Pressure (IOP). Nonetheless, when detected early it can be successfully treated. The Eye Center provides diagnosis and treatment of all types of Glaucoma including Primary Open Angle Glaucoma and Angle Closure Glaucoma
The Eye Center is conveniently located for patients concerned about Glaucoma or needing an eye examination for Glaucoma from Denver, Aurora, Arvada, Wheat Ridge, Westminster, Highlands Ranch, Parker, Conifer, Evergreen, Pine, Bailey, Englewood, Littleton, Sheridan, Cherry Hills Village, Northglenn, Broomfield and Greenwood Village. If you, a family member or friend, would like to schedule an eye examination for Glaucoma, please call The Eye Center in Denver, Colorado at 303-777-5455.