Glaucoma is a group of eye conditions that can cause damage to the optic nerve. The optic nerve is responsible for transporting visual information from the eye to the brain, thus, its health is vital for good vision. The damage often (but not always) is caused by abnormally high pressure in the eye.
With time, the increased pressure can erode the optic nerve tissue leading to vision loss and sometimes blindness. Vision loss from glaucoma cannot be recovered but if recognized early, it can be slowed down and prevented. Glaucoma is the leading cause of blindness for individuals above the age of 60.
Types of Glaucoma
There are five major types of glaucoma and they include:
- Open Angle (Chronic) Glaucoma: Chronic or open angle glaucoma does not present any symptoms apart from gradual vision loss. It is the most common type of glaucoma and the vision loss can develop slowly causing the patient to suffer irreparable damage before any other symptoms become apparent.
- Angle-Closure (Acute) Glaucoma: The sudden blockage of the aqueous humor fluid can cause a rapid build-up of the fluid thus resulting in severe, quick, and painful increase in pressure. Acute glaucoma is an emergency situation and you should call a doctor immediately if you start experiencing sudden symptoms of severe pain, nausea, and blurred vision.
- Congenital Glaucoma: Children with congenital glaucoma have a defect in the angle of their eyes which prevents or slows down normal fluid drainage. It presents symptoms such as excessive tearing, sensitivity to light, and cloudy eyes. Congenital glaucoma is genetic.
- Normal tension Glaucoma: In some cases, individuals can develop damage to their optic nerve without increased eye pressure. The cause is unknown but lack of blood flow or extreme sensitivity to the optic nerve can be a factor in this type of glaucoma.
- Secondary Glaucoma: This is often a side effect of another eye condition or injury such as eye tumor or cataracts. Some types of medication can also cause this type of glaucoma.
Causes of Glaucoma
A clear fluid known as aqueous humor (liquid produced by the eye) is continuously made in the eye. As it is made, it fills the front of the eye and exits through channels at the junction of the cornea and iris. If these channels are partially obstructed or blocked, the intraocular pressure (IOP) which is the natural pressure may increase causing damage to the optic nerve. As the damage in the optic nerve progresses, it can lead to loss of sight.
The exact cause of pressure in the eye is not always known but some of the factors that play a role include:
- Developing Cataracts
- Certain medications
Symptoms of Glaucoma
The open-angle glaucoma is the most common type of glaucoma and it does not have any symptoms apart from gradual loss of vision.
Acute-angle glaucoma is a medical emergency and you should seek immediate medical attention if you are experiencing the following symptoms:
- Severe eye pain
- Sudden vision disturbances
- Redness in the eye
- Sudden blurred vision
- Seeing colored rings around lights
Risk factors of Glaucoma
Risk factors of developing glaucoma include:
- Being above the age of 60
- Having high intraocular pressure which is raised internal eye pressure
- Being of certain ethnicities such as Black, Hispanic, or Asian
- Having corneas that are thin at the center
- Having a family history of glaucoma
- Being extremely far-sighted or near-sighted
- Having undergone certain types of eye surgery or had an eye injury
- Taking certain medication such as corticosteroids for a long time
Glaucoma is diagnosed by an ophthalmologist by performing a comprehensive eye examination to check for signs of deterioration such as loss of nerve tissue. Several tests may be performed including:
- Tonometry to measure the intraocular pressure
- Visual field tests to look for areas of vision loss
- Pachymetry to measure corneal thickness
- Gonioscopy to inspect the drainage angle
- Imaging tests to inspect for optic nerve damage
Treatment of Glaucoma
Damage caused by glaucoma is irreversible but early treatment can help manage the condition by slowing down or preventing vision loss.
Glaucoma is treated by lowering the intraocular pressure and your ophthalmologist can prescribe one of the following or a combination of them:
- Medications which will include eye drops or pills
- Surgery and other forms of therapies with the aim of improving drainage fluid within the eye thus lowering the pressure. These include:
- Filtering surgery, also known as trabeculectomy, which involves the surgeon creating an opening in the sclera (white part of the eye) and removing part of the trabecular meshwork.
- Minimally invasive glaucoma surgery to lower the intraocular pressure which is often combined with cataract surgery.
- Drainage tubes can be inserted in the shunt in the eye to drain excess fluid and lower the intraocular pressure.
- Laser therapy, also known as laser trabeculoplasty, is an option for treating open-angle glaucoma. It involves an ophthalmologist using a small laser beam to unclog channels in the trabecular meshwork.
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