How can a loss of vision be silent? Well, there are 2 main parts of our vision:
- Our CENTRAL vision that gives us details that we notice everyday
- Our PERIPHERAL or side vision, which we often don’t pay too much attention to.
Glaucoma first affects this peripheral vision before getting anywhere near the central vision. This is why it’s called the silent thief of vision because we often don’t notice our side vision shrinking over time until it’s too late!
To understand glaucoma, we have to first explore what part of the eye it affects. Our eye is connected to the brain through a cable-like connection known as the OPTIC NERVE. Glaucoma is often associated with a higher eye pressure but can still occur with a normal eye pressure. Wait… we have an EYE PRESSURE? Yes! Just like you have fluid in your body, you also have fluid in the eyes; this fluid is constantly being drained and produced and there has to be a balance between these processes. An imbalance puts stress on and damages the optic nerve, which then leads to vision loss (first peripheral vision, then eventually central vision if left untreated).
If glaucoma is a silent thief of vision, how do we catch it? That’s where you need the help of an OPTOMETRIC DETECTIVE (A.K.A. your optometrist)! Early detection is the KEY to preventing damage of the optic nerve. Your eye care practitioner has many tools to detect early changes that we normally can’t see ourselves. These include:
- OCT TESTING: a machine that measure the thicknesses of the optic nerve over time (glaucoma causes the optic nerve to get thinner) + images the draining system in eye & more
- VISUAL FIELD TESTING: a machine that picks up on early side vision loss
- INTRAOCULAR PRESSURE TESTING: a machine that measures the eye pressure
There are 4 main types of glaucoma and most of them are painless – another reason why glaucoma gets it’s silent thief title:
|Glaucoma Type||Brief Description|
|1. Primary Open Angle Glaucoma||Most common, painless and associated with a higher eye pressure. In Ontario, this type of glaucoma can be managed by an optometrist without a referral to an ophthalmologist.|
|2. Angle Closure Glaucoma||Uncommon but associated with symptoms of nausea, eye pain/pressure, red eyes, blurred vision, halos around lights. This is a medical emergency and should be seen A.S.A.P.|
|3. Secondary Glaucoma||Caused by injury, infection, medications, certain medical conditions, rarely a tumor, etc. In Ontario, this type of glaucoma should be managed by an ophthalmologist (eye specialist) or co-managed by an optometrist and ophthalmologist.|
|4. Normal Tension Glaucoma||Damage is happening to the optic nerve but the eye pressure is in a normal range. This type of glaucoma must also be referred (as above) in Ontario.|
There are a few common risk factors to watch out for (to name a few):
- AGE (increased risk over 60)
- FAMILY HISTORY
- EYE INJURIES
- ETHNICITY (increased risk for Asians, African Americans, Hispanic)
- CERTAIN MEDICAL CONDITIONS (blood pressure variations, heart disease, diabetes)
- CORTICOSTEROID USE
Glaucoma is one complicated vision thief and although the exact cause is still unknown, the mainstay of treatment is to reduce the eye pressure. There is no cure for glaucoma yet, however, the aim is to delay any progression of the disease by catching it EARLY.. This can be done through 2 main methods:
- MEDICATIONS/EYE DROPS
So if you want to catch this silent thief, make sure you visit your eye care practitioner for regular eye examinations!
Dr. Manvit Singh