What is Glaucoma?
Often referred to as the “Silent Thief of Vision”, glaucoma is the second leading cause of blindness in the United States. With the exception of narrow angle glaucoma, it generally has no symptoms until irreversible damage to vision has begun.
Glaucoma is the name given to a category of eye diseases in which a dangerous buildup of internal eye pressure damages the optic nerve of the eye. Though its cause isn’t entirely clear, experts believe it is often a progressive condition where excess intraocular fluid builds up until the pressure begins to damage the delicate optic nerve of the eye, resulting in loss of vision. Current studies also indicate that glaucoma may be caused by other factors as well, including poor blood supply to the nerves and genetic predispositions. Most patients experience a reduction in peripheral vision followed by loss of central vision. Typically both eyes are not affected equally.
Fortunately, glaucoma can be detected early during a routine eye exam, and if treatment is begun, further loss of vision can be minimized.
Glaucoma can happen to anyone, and doesn’t always fit within a predefined profile. We do know that people at an increased risk for developing the disease are those that:
- Have a family history of glaucoma
- Are over age 40
- Are nearsighted or farsighted
- Are of African American or Hispanic descent
- Are diabetic or hypertensive
- Have used steroids or cortizone for a long period of time
- Have suffered an eye injury in the past
Those who have a first degree relative with glaucoma are at a nine times greater risk of developing the disease.
Types of Glaucoma
In open-angle glaucoma, fluid in the eye doesn’t drain properly and the fluid build-up causes pressure that may damage the optic nerve of the eye. With that being said, up to half of the patients suffering from open-angle glaucoma do not have abnormally high intraocular pressure. This form of open-angle glaucoma is called normal- or low-tension glaucoma. Normal-tension glaucoma is more common in those who are Japanese, are female and/or have a history of vascular disease.
Closed-angle glaucoma is also known as angle-closure, or acute narrow-angle glaucoma. In closed-angle glaucoma, fluid cannot flow out of the eye because the drainage angle is blocked. This can occur due to a variety of factors:
- the iris and lens are blocking movement of fluid and the resulting pressure causes the iris to press on the eye’s drainage system
- A defect in the iris which causes it to fall forward and block the drainage angle
- Scar tissue between the iris and cornea blocks the eye’s drainage system
This condition is a medical emergency and requires immediate treatment.
Congenital and Infantile Glaucoma
Certain birth defects that occur because of an infection in the mother during pregnancy (such as rubella), or because of an inherited condition such as neurofibromatosis, can cause glaucoma to be present at birth or to develop during the first few years of life.
Secondary glaucoma can occur after eye surgery or an eye injury. It may also be brought on by a cataract or after taking medicines that contain corticosteroids.
Signs of Glaucoma
Open-Angle Glaucoma Symptoms
Most patients experience no symptoms until late in the disease, after significant vision loss has occurred. This is primarily due to the less affected eye making up for the vision loss. Typically a reduction in side-vision acuity is noticed first, followed by a progressive loss in field of vision.
Closed-Angle Glaucoma Symptoms
Closed-angle glaucoma symptoms range from none to severe and usually only affect one eye at a time and may include:
- Sudden, severe blurring of vision
- Severe pain in or around the eye
- Dilated pupils
- Colored halos around lights
- Redness of the eye
- Nausea and vomiting
Symptoms of closed-angle glaucoma may be episodic, only occurring in the evening and disappearing by morning. Each episode will permanently damage your vision. Closed-angle glaucoma can also happen suddenly and requires immediate medical attention to prevent permanent vision loss.
Congenital Glaucoma Symptoms
Symptoms of glaucoma present at birth or that develops in the first few years of life may include:
- watery eyes
- sensitivity to light
- an eye or eyes that look cloudy
- eyes that look larger than normal as a result of high pressure
- frequent rubbing of the eyes, squinting, or keeping the eyes closed much of the time
Glaucoma Testing & Prevention
During your next comprehensive eye exam, your doctor will check the following to determine if you are at risk for glaucoma:
- Eye structure (Ophthalmoscopy, gonioscopy, slit lamp exam, GDx Imaging, and optic coherence tomography)
- Eye pressure (tonometry)
- Visual acuity and perimetry tests
- Cornea thickness (ultrasound pachymetry)
Routine eye examinations for early glaucoma detection and treatment are key to preserving your vision. There is no cure for glaucoma, however medications and surgery should limit further vision loss. Treatment for glaucoma will likely continue for the patient’s lifetime. There are counselors available who specialize in helping patients adjust to living with low vision.
The type of treatment prescribed will vary depending on the type of glaucoma targeted.
Treatment for Open-Angle Glaucoma
Your eye doctor will regularly check the pressure for each eye, adjust your medicine, and perform other treatments as needed. Medicine usually consists of eye drops to either decrease fluid production or enhance its outflow. This treatment for glaucoma aims to slow the damage to the optic nerve by relieving the pressure in the eyes.
Eyesight for adults that has already been lost cannot be restored, however some of the damage that occurs in children due to congenital glaucoma can be reversed. Your eye doctor may also elect to use laser treatment or surgery to treat the glaucoma.
Treatment for Closed-Angle Glaucoma
A common treatment for closed-angle glaucoma is a procedure called laser iridotomy in which a small hole is created on the outer edge of the iris, allowing fluid to flow between the eye chambers. In general, little or no pain is felt during laser iridotomy. Additional medicine (usually eye drops) may be needed to maintain the desired eye pressure.
Treatment for Acute Closed-Angle Glaucoma
Acute closed-angle glaucoma is a painful condition which requires immediate laser treatment. A sudden increase in pressure to the eye due to fluid blockage can result in rapid damage to the optic nerve.
Treatment for Congenital Glaucoma
In most cases, congenital glaucoma requires surgery to lower eye pressure. Medicine may also be prescribed.