Glaucoma

Primary open angle glaucoma

Patients with this disorder may not know they have glaucoma. There are no symptoms with early disease. With advanced disease, patients may note gradual loss of peripheral (side) vision and even central vision.

Acute angle closure glaucoma

Patients with this type of glaucoma may experience sudden, intense eye pain. Symptoms of this type of glaucoma include:

• Severe pain in the eye
• Nausea and vomiting
• Blurry vision
• Halos around objects
• Eye redness
• Headache (particularly above the eyes)

A sudden (acute) attack of severe eye pain along with nausea or vomiting indicates a serious disorder. Call 911 or have someone drive you to the Emergency Department without delay.

Risk factors include:

• High eye pressure (Intraocular pressure or IOP)
• Aging
• Diabetes
• Family history of glaucoma
• Nearsightedness
• Hypothyroidism/Hyperthyroidism
• Retinal venous occlusion
• Previous eye surgery
• African American, Asian, Hispanic descent
• Corticosteroid use
• Thin corneas (the clear surface of the eye)

As it is rare to have symptoms in early disease, glaucoma should be diagnosed with an eye exam. A baseline examination at age 40 would be recommended and follow-up based on the risk for disease. These exams include:

• Visual field test
  This simple test is performed to determine if any changes have occurred in your peripheral (side) vision. Often, your eye care provider will hold fingers up off to the side and ask you to identify the number of fingers present without turning your head. A more formal visual field test would involve looking at a target and pressing a button when you see a light. 
• Tonometry
  This test is performed during a routine eye exam and measures the intraocular pressure within the eye. The eyes are numbed first with eye drops.
  
• Slit-lamp exam
  Another common eye exam is performed with the slit-lamp, which is a microscope combined with a bright light source. Your eye is magnified several times with the slit lamp. An eye exam with this machine allows your ophthalmologist or optometrist to view structures within the eye, especially the cornea, sclera, iris, lens, vitreous, and retina. You will be asked to sit forward and place your chin on a chin rest and your forehead against the machine. You may have a small amount of orange dye (fluorescein) placed in your eyes and your eyes may be dilated using eye drops.
  
• Dilated Fundus (Funduscopy) exam
  This exam allows your ophthalmologist or optometrist to examine your eyes' blood vessels, vitreous, optic nerve, macula and retina. After dilating your eyes, your doctor will view these internal structures with a light source that directs the light into your eyes. This exam is especially useful in glaucoma to get a careful look at the optic nerve.
  
• Optic nerve head imaging
  In the evaluation of glaucoma, it is important to document the health of the optic nerve. We do that by either taking a photograph or using machines that will measure the optic nerve. This test may be repeated periodically especially if a change in the nerve is suspected.

Even though we do not know the actual cause of glaucoma, a proven treatment is to lower the eye pressure. We can do that in several ways:

• Topical medicines (eye drops)
  Prescription eye drops are often the first line of treatment to help reduce pressure within the eye. Your ophthalmologist may prescribe one or more eye drops, each of which has a different mechanism of action to either decrease eye fluid (aqueous humor) production or increase fluid outflow from the eye back into the bloodstream.
  
• Oral medications
  Your ophthalmologist may prescribe another medication in addition to eye drops, especially if eye drops alone do not help bring down intraocular pressure. This additional medication may be a class of drug called a carbonic anhydrase inhibitor that decreases the production of fluid (aqueous humor) within the eye. There are several kinds of carbonic anhydrase inhibitors on the market. They are not used regularly because of possible side effects but are often used in an emergency.
  
• Laser treatment
  Laser treatment may be recommended if you cannot tolerate eye drop(s) or if the eye drops do not lower intraocular pressure sufficiently. Laser treatment can also be considered before eye drops, depending on the situation. A laser procedure, called trabeculoplasty, has been used with success in patients with primary open angle glaucoma. During treatment, a laser beam is directed at the drainage channel between the iris and cornea to cause a "remodeling" of the drainage pathway to increase fluid outflow. This procedure is performed in your ophthalmologist's office and usually takes 10 to 20 minutes, although you may be in clinic for a couple of hours after the laser procedure.
  
• Surgery in the operating room
  Your ophthalmologist may instead recommend a surgical procedure, called trabeculectomy, in which a bypass pathway for eye fluid is created. You will have some mild sedation and your eye will be numbed for this procedure. A flap is made in the sclera (white portion of the eye) and a hole in the front chamber of the eye is made underneath the flap. This creates a new pathway for fluid to get out of the eye, thereby lowering the pressure. However the flap is then partially closed to keep the eye pressure from getting too low. Another surgery often used for glaucoma is placement of a drainage tube in the eye. This also bypasses the normal drainage pathway by placing a tube in the front chamber of the eye that drains under a plate (under the clear covering of the eye, called the conjunctiva) and back to the blood stream. This procedure is done in the operating room similar to a trabeculectomy.
  
• Treatment for acute angle closure glaucoma
  A sudden attack of glaucoma is treated first in the Emergency Department with eye drops and other medications to help reduce pressure within the eye. Laser surgery (iridotomy) may be recommended to permanently relieve ocular pressure. This procedure creates a small hole in the iris that allows the aqueous fluid to flow freely into the channel between the iris and cornea.