Glaucoma is the leading cause of irreversible blindness. More than 60 million people around the world have glaucoma, including more than 3 million Americans. Because symptoms often start slowly, many people don’t know they have the disease until later, more advanced stages.
Glaucoma is a complex disease that affects the optic nerve. The optic nerve is actually a collection of more than a million nerve fibers that transmit visual information to the brain. Damage to the optic nerve leads to vision loss. Changes in vision usually start with a gradual decrease in peripheral vision, while the central vision remains crisp and sharp. Advanced glaucoma can cause ‘tunnel vision’ and lead to blindness.
Types of Glaucoma and Related Symptoms
There are two main types of glaucoma based on the anatomy of the eye’s drainage pathway. Your eyes continually produce a clear fluid inside the front of the eye called aqueous humor. It nourishes the eye and keeps it healthy. (This liquid is different from tears which are outside the eye.) When the aqueous cannot drain from the eye properly, eye pressure increases and impairs the retinal nerve within the eyes, and eventually damages the optic nerve.
- Often there are no symptoms.
- Once you notice vision loss, it’s likely very advanced.
- This is the most common type of glaucoma.
Acute angle-closure glaucoma
- Hazy or blurred vision
- Halos around lights
- Severe eye pain and headache
- Red eye
- Nausea and vomiting
- Sudden vision loss
Glaucoma Risk Factors
- Age: adults older than 60 years of age are at six times greater risk than younger people.
- Race: African Americans and Hispanics are at three to four times greater risk than Caucasians. Asians and Native Americans are at increased risk of angle-closure glaucoma.
- Family history of glaucoma
- Thin corneas
- Type 2 diabetes
- Increased eye pressure, the only modifiable risk factor for glaucoma.
All glaucoma treatments are designed to reduce intra-ocular pressure, also known as IOP. A lower IOP is better: a normal pressure ranges from 10 to 21 mm Hg.
The American Academy of Ophthalmology recommends that all adults have a comprehensive eye exam by age 40. During this exam, your optometrist or ophthalmologist will screen for glaucoma as well as other eye conditions. A comprehensive examination includes evaluation for glaucoma through measuring the intraocular pressure, evaluating the optic nerve, and evaluating the anatomy of drainage angle of your eyes. Your eye care professional may recommend additional tests to screen for glaucoma or other eye conditions based on the results of your comprehensive examination and your risk factors. He or she will also prescribe the recommended interval for subsequent examinations.
If indicated, additional testing for glaucoma may include:
- A visual field test to measure your peripheral vision
- Measurement of corneal thickness
- Measurement the thickness of the retinal nerve fiber layer
These measurements can determine your risk for glaucoma as well as whether damage has occurred due to glaucoma.
There is no cure for glaucoma, but many treatments can help successfully manage the condition by reducing eye pressure in order to reduce further vision loss.
Several classes of topical medications (eye drops) can help lower IOP by decreasing fluid production and/or increasing fluid outflow. If you have heart or lung disease or are allergic to sulfa drugs, talk with your doctor about finding the right medication for you.
Laser trabeculosplasty is a quick, painless, in-office procedure that can help lower IOP in about 80 percent of patients treated. It can lose its initial effect over time but can be repeated, and is considered low risk. A laser iridotomy is another laser treatment that’s performed to open the drainage angle in patients with narrow or closed angle glaucoma.
Surgery lowers IOP by opening the eye’s existing fluid drainage pathway or bypassing the natural drainage to create a new pathway for fluid to drain from the eye. Over the past decade, several new surgical procedures have been developed known collectively as Minimally Invasive Glaucoma Surgery (MIGs). These procedures help reduce eye pressure with an improved safety profile compared to traditional glaucoma surgery. Your doctor will discuss surgical treatment options with you if surgery is indicated.
As with many health conditions, early detection of glaucoma is key. All patients age 40 and over should have a comprehensive eye examination. Your eye doctor will recommend the frequency of subsequent examinations based on your risk factors. If glaucoma is detected and treated early, further vision loss and blindness can often be prevented.