Glaucoma is one of the leading causes of irreversible blindness in the United States and world-wide. In glaucoma, destruction to the ocular nerve cells and their axons causes damage to the optic nerve resulting in permanent vision loss. While there are a number of risk factors for glaucoma, elevated intraocular pressure (IOP) is considered to be the most significant. Elevated IOP occurs when aqueous humor (the clear fluid inside the eye necessary for intraocular nutrition) drains more slowly than it is produced. It is not known whether elevated IOP is the direct cause or just a contributing factor for damage. There are cases where elevated IOP causes no damage. There are a many types of glaucoma, most of which are asymptomatic until the late stages. Early detection is the key to limiting damage from this insidious disease.
Ocular Hypertension – Individuals with higher than normal IOP who have no signs of disease. The appearance of the optic nerve (structure) as well as visual fields (function) is considered healthy and normal.
Glaucoma Suspects – Individuals classified as glaucoma suspects have risk factors for developing glaucoma and/or show questionable clinical findings. These patients should be monitored closely to check for conversion to glaucoma.
Chronic Open–angle Glaucoma – In this most common form of the disorder, the drainage pathway is open. This determination is made with a special contact lens placed on the eye, called a gonioscope. Open angle glaucoma may be classified as primary or secondary. Primary open-angle glaucoma is generally a disorder seen in patents over the age of 40 years where there is no obvious reason for obstructed drainage. In secondary open-angle glaucoma, the IOP elevation results from conditions causing deposition of pigment or other material into the drainage meshwork, damage from trauma to the eye, or as a result of chronic steroid use.
Closed–angle Glaucoma – Closed angle glaucoma is the result of anatomical structures that physically block the drainage mechanism. Risk factors to this form of glaucoma are substantial far-sightedness, small eyes, and older age. People of Asian descent are predisposed to this form of glaucoma. Angle closure may be insidious but is often acute. The resulting spike of IOP results in a red painful eye that should be treated as an emergency and managed promptly. A thorough eye examination can detect patients that are risk for angle closure so they can be considered for a procedure to prevent an acute angle closure from occurring.
Normal Tension Glaucoma – In some individuals, what is considered to be normal IOP can result in damage to the optic nerve. This situation may be related to insufficient blood flow to the optic nerve or abnormally susceptible optic nerve fibers. This type of glaucoma is managed in a similar manner as other forms of open angle glaucoma.
Congenital Glaucoma – Congenital glaucoma occurs when a child is born with a deficiency in the drainage system of the eye. It may be the result of a malformation of the ocular drainage system or other eye conditions. The disease usually affects male children, with both eyes usually being involved. Since the ocular tissues of a child under age 3 are very elastic, the eye becomes enlarged. Symptoms include enlarged eye, light sensitivity, tearing, and corneal clouding.
- People Over 60 (6x greater risk)
- Eye Injury (Immediately or years later)
- High myopia (Nearsightedness)
- Family History of Glaucoma: (4-9x greater risk)
- African-Americans (6-8x more risk than Caucasians)
- Hispanics (In older age groups)
- Asians (Angle Closure)
- Steroid Use (Oral, Drops, Injections, Inhalers)
- Vascular Conditions such as migraine or vasospastic dysregulation.
- Central Corneal Thickness less than .5 mm (Measured with a simple procedure in the office)
Treatment: There is no cure for glaucoma but it can be managed with medication, laser treatment, and surgery. These methods manage this disease by either decreasing production or increasing outflow of the aqueous humor. This results in lower intraocular pressure. Research is now being conducted to determine the effectiveness of treatment options that will actually protect the nerve fibers independent of pressure control. The best defense is regular eye examinations. The earlier this condition is detected, the greater the prognosis for long term visual preservation.