Glaucoma

Glaucoma is an eye disease that often occurs without any obvious symptoms. Many people don't discover they have glaucoma until the disease is advanced. In fact, 50% of the estimated 3 million Americans that have glaucoma are unaware they have it. Scheduling glaucoma screenings on a regular basis is the most effective way to detect and manage this eye disease. Once glaucoma is diagnosed, management of the disease may help slow the progression and preserve a patient's remaining vision.

What Is Glaucoma?

Clear fluid called aqueous humor is produced and circulates in the front portion of the eye. This fluid nourishes the front part of the eye and is largely responsible for maintaining the pressure inside the eye. In a healthy eye, the eye produces a small amount of aqueous humor and an equal amount of this fluid flows out of the eye to maintain a healthy eye pressure which the doctor measures as intraocular pressure (IOP). When the aqueous fluid doesn’t flow out of the eye properly, it causes pressure to build up in the eye. If left untreated, elevated IOP causes damage to the optic nerve fibers and may lead to blindness.

Peripheral (side) vision is usually affected by glaucoma first. If the disease is not treated, vision loss may progress and can lead to total blindness over time.

There are several types of glaucoma, the most common being open-angle glaucoma. In its early stages, there are no symptoms and vision is normal. As the optic nerve becomes more damaged, vision may be compromised, but at such a gradual rate symptoms are virtually absent until very advanced disease is present. Once the optic nerve is damaged and vision compromised, it cannot be reversed or repaired. Early detection and appropriate treatment is the best way to preserve eyesight for glaucoma patients.

One type of open-angle glaucoma is known as normal or low-tension glaucoma. Patients with this type of glaucoma have statistically normal IOP measurements, but develop the same optic nerve and visual field findings as other open-angle glaucoma patients. As ophthalmologists have learned more about open-angle glaucoma, nearly 30% of newly diagnosed glaucoma patients have normal IOP during the examination. Clearly, glaucoma is a disease that is more than just elevated IOP.

Closed-angle glaucoma is a less common form of glaucoma, but one that requires immediate treatment as a medical emergency. Usually eye pressure rises quickly due to the iris blocking some or all of the drainage angle. Symptoms include, but are not limited to:
  • Headache
  • Severe eye or brow pain
  • Nausea
  • Vomiting
  • Blurred vision
  • Seeing halos
  • Redness of the eye
People at risk of developing closed-angle glaucoma include those of Asian descent and farsighted individuals.

Acute angle closure glaucoma is a medical emergency. Seek medical help immediately.

Congenital glaucoma is rare and can develop in infants and young children. It appears to have a hereditary component.

Secondary glaucoma results from another eye condition or disease. Causes may be from an eye injury, long-term use of steroids, or the presence of tumors.

It’s important that regular eye exams include an IOP check as well as an optic nerve exam if there’s reason to believe that even though an IOP appears normal, there may be a risk factor for glaucoma.


How Is Glaucoma Diagnosed?

A glaucoma evaluation may include measuring eye pressure, inspecting the eye’s drainage angle to determine the type of glaucoma, inspecting the optic nerve for signs of damage, testing peripheral vision (visual field), and measuring the thickness of the cornea.

Our goal is to prevent vision loss from glaucoma before it is clinically apparent to the patient. Therefore, patients should schedule regular glaucoma screenings. With increasing life expectancy, patients should be continually monitored to help them maintain healthy vision throughout their lives.


What Are the Risk Factors for Glaucoma?

Risk factors that have been identified for glaucoma include the following:
• High intraocular pressure
• Family history of glaucoma
• African-American ancestry
• Optic nerve morphology
• High myopia (nearsightedness)
• Smoking
• Coexisting vascular disease

How Is Glaucoma Treated?

The goal of glaucoma treatment is to prevent vision loss or, if the patient already has vision loss from glaucoma, to try and prevent further vision loss. Eye drops, oral medication, laser treatment, surgery, or a combination of treatments may be used to manage glaucoma. Treatment does not restore vision that has already been lost, but it may prevent or minimize further damage from occurring.

Medication

IOP is measured during periodic evaluations as recommended by Dr. Johnson, generally every three to six months. It’s important to remember measuring IOP only provides a reading of the pressure at that moment. It may be different (higher or lower) later the same day, the next day, the next week, or the next month. That’s why any single IOP measurement is only part of a complete evaluation. At McCormick Eye Center, a glaucoma treatment plan can best be determined after a comprehensive eye exam.

Medication in the form of eye drops is the usual method of glaucoma treatment in the United States. The majority of glaucoma patients can control their intraocular pressure this way. At McCormick Eye Center, Dr. Johnson monitors both the effectiveness of the treatment and the side effects.

Laser Treatment

Some patients may benefit from surgery when glaucoma treatment medications produce undesirable side effects. Laser glaucoma treatment is an outpatient procedure that requires only topical anesthesia and generally takes less than fifteen minutes to complete. Although laser treatment is not an option for everyone, it has been proven to decrease intraocular pressure in many patients. The full effect of the treatment may take about three to six weeks.

Surgical Treatment

Glaucoma surgery is usually reserved for patients whose intraocular pressure has not been controlled by the use of medication or laser treatment. The goal of surgery is to lower the intraocular pressure by making a small opening in the eye so that fluid may leave the eye through the newly formed hole. Many techniques have evolved to allow better regulation of fluid outflow, but there is the potential of post-operative complications. This is why this method of glaucoma treatment is usually reserved for those patients who are unresponsive to medical and/or laser treatment. After a comprehensive evaluation, Dr. Johnson can determine whether surgery is the most appropriate treatment for you.




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