Glaucoma is a leading cause of vision loss in Americans*1. This eye disease permanently damages the optic nerve, which carries visual information from your eyes to your brain. There are different types of glaucoma but they all have one thing in common – they increase the pressure in your eyes and this damages your optic nerve.
What controls the pressure in your eyes?
Your eyes contain a fluid called the aqueous humor, which is full of nutrients that help keep your eyes healthy. Normally, the aqueous humor drains out of your eyes at the same rate that your eyes produce it, meaning there’s a constant cycle of fresh aqueous humor to nourish your eyes.
If too much aqueous humor is produced or it can’t drain out of your eyes properly, it builds up and increases the pressure in your eyes.
How does increased pressure in your eyes damage your optic nerve?
If the pressure in your eyes rises quickly, this can reduce the blood supply to your optic nerve, which will damage it. It isn’t clear how a gradual rise in pressure causes damage to your optic nerve.
Lowering the pressure in your eyes is proven to slow down the progression of glaucoma and helps preserve your vision.
What are the different types of glaucoma?
There are 2 main types of glaucoma – open-angle glaucoma and angle-closure glaucoma. Of the 3 million Americans who have glaucoma, 90% have open-angle glaucoma.
Open-angle glaucoma happens when the drainage channels of the eye become clogged. A good analogy is a sink that won’t drain, even though the drain is clear because the pipe connected to it is clogged. Open-angle glaucoma usually develops slowly.
Angle-closure glaucoma happens when the opening of the eye’s drainage channel becomes blocked. This happens when the iris (the colored part of your eye) covers the opening of the drainage channel. A good analogy is a piece of paper sliding over a drain, which stops the sink from draining. Angle-closure glaucoma usually happens suddenly (acute) but can also develop gradually (chronic).
Who is at risk of glaucoma?
Risk factors for developing glaucoma include:
- age – glaucoma is more common in people over age 40
- race – you have a higher risk of developing glaucoma if you’re of African, Asian, or Hispanic heritage
- family history – if a close family member has glaucoma, you’re more likely to develop it and should have regular eye examinations
- certain medical conditions – diabetes, high blood pressure, migraines, poor blood circulation, and other conditions that affect your whole body increase your risk of glaucoma
- certain medications – long-term steroid use increases your risk of glaucoma
Other risk factors include past eye injuries, thin corneas, and a thinning optic nerve.
What are the symptoms of glaucoma?
Open-angle glaucoma often has no symptoms until it’s more advanced. You won’t feel any pain or notice any changes in your vision. This is why it’s important to have regular eye exams to detect early signs of open-angle glaucoma. As open-angle glaucoma progresses, you may notice reduced side vision.
In contrast, angle-closure glaucoma has several symptoms, including:
- severe eye and head pain – you may wake up in the night with severe pain in one eye
- red eye
- hazy or blurred vision – you may also notice halos around bright lights
- nausea or vomiting
- sudden vision loss
Angle-closure glaucoma can cause sudden and permanent vision loss. If you have any of these symptoms, see your eye doctor right away.
How is glaucoma diagnosed?
To check whether you have glaucoma, your eye doctor will:
- measure the pressure in your eye using a device called a tonometer
- measure the thickness of your cornea using a device called a pachymeter
- test your side vision
- examine your optic nerve by taking a photograph and scan of it
- examine the area where fluid drains out of your eyes using a special lens.
These tests are all quick, painless, and non-invasive.
How is glaucoma treated?
There are several treatments for open-angle glaucoma. Your eye doctor will recommend the best one for your individual case. Treatments include:
- daily glaucoma eye drops – there are different types of eye drops, including:
- eye drops to reduce fluid production by your eyes e.g. alpha-agonists, beta-blockers, and carbonic anhydrase inhibitors
- eye drops to increase fluid drainage out of your eyes e.g. miotics and prostaglandin analogs
- trabeculoplasty – laser surgery to unblock the drainage channels of your eyes.
Angle-closure glaucoma is first treated with powerful drugs to rapidly reduce the pressure in your eye. Once the pressure is reduced, you will most likely need laser surgery (iridotomy) or conventional surgery (iridectomy) to make a hole in your iris that will allow fluid to drain out of your eye. This surgery will usually be repeated in your other eye to reduce your risk of developing angle-closure glaucoma in that eye as well.
*1 Glaucoma Research Foundation