Early Signs of Glaucoma

Our sight is one of our most valued senses. Our eyes allow us to perceive the world around us and fully enjoy life’s experiences. However, certain conditions like glaucoma can threaten our vision and lead to irreversible vision loss. According to the World Health Organization, glaucoma is one of the leading causes of vision loss worldwide. Despite its prevalence, many are unaware that they even have it.

Glaucoma typically doesn’t cause symptoms until later stages, which is why it’s essential to have regular comprehensive eye exams. Your optometrist has the diagnostic tools and skills to detect the most subtle indicators of the condition.


Glaucoma is a group of eye conditions that damage the optic nerve, which is responsible for communicating information like shapes, colours, and words from our eyes to the brain.

The damage is often caused by increased pressure within the eye—called intraocular pressure or IOP—and the condition can develop at a snail’s pace over a long period of time, eventually leading to partial or complete permanent vision loss. There are a few different types of glaucoma, including:

  • Open-angle glaucoma is the most common type where the IOP gradually and silently builds

  • Angle-closure glaucoma occurs when the fluid in the eye doesn’t drain properly, causing a drastic increase in IOP and sudden, severe effects

  • Normal-tension glaucoma is the outlier because the optic nerve becomes damaged when IOP still falls in the normal range

Early symptoms are often nonexistent in all types of glaucoma until you develop vision loss. Regular comprehensive eye exams are critical in detecting the changes to the inner structures of your eyes.

What Causes Glaucoma?

Increased IOP is the primary cause of glaucoma, but certain factors can heighten your risk of developing the condition, including:

  • Age

  • Ethnicity

  • Family history

  • Corneal thinness

  • Optic nerve thinning

  • Long-term steroid use

  • Medical history of diabetes, migraines, or high blood pressure


Your optometrist will perform in-depth exams to monitor your eyes for risk of glaucoma. If you have one or more risk factors they may see you back more frequently to make sure glaucoma is caught early.

Detecting Glaucoma: Increased Eye Pressure

The most common early warning sign of glaucoma is increased intraocular pressure (pressure inside the eye). When eye pressure is too high, it can damage the optic nerve and lead to vision loss. But eye pressure isn’t something you can measure on your own.

During a routine eye exam, your optometrist can measure your IOP using a tonometry test. If your eye pressure is elevated, further testing may be recommended to determine if it is a sign of glaucoma. 

Some additional tests include:

  • Inspecting your eye’s drainage angle

  • Visual field testing to assess peripheral vision

  • Measuring corneal thickness

  • Examining ocular blood vessels and the optic nerve

Vision Changes

As mentioned earlier, glaucoma often doesn’t cause symptoms until its later stages. However, some people with early glaucoma may experience subtle vision changes, such as blurry vision or difficulty seeing in low-light conditions. Paying attention to any changes in your vision and reporting them to your optometrist is important.

Family History

Because family history is a risk factor for glaucoma, it’s essential to let your optometrist know if any of your relatives have been diagnosed with glaucoma. Whether your mom, sibling, or grandparents develop the condition, this information can help determine if you need more frequent eye exams or earlier testing for glaucoma.


If, between annual eye exams, your vision begins to deteriorate, it’s important to seek care sooner than later to help preserve your sight. Angle-closure glaucoma often has an immediate onset, and the severe symptoms require emergency care. See your optometrist as soon as possible if you experience symptoms such as:

  • Eye pain

  • Nausea

  • Eye redness

  • Sudden vision problems

  • Halos around light

  • Unexpected blurry vision


While glaucoma often doesn’t cause symptoms in its early stages, there are some subtle signs your optometrist can investigate before making a diagnosis. Your IOP can be an important indicator, but family history and vision changes can cause optic nerve damage without eye pressure changes.

Total vision loss is avoidable when you get proper management and treatment. It’s important to have regular eye exams so your optometrist can detect glaucoma early and take steps to preserve your vision. Contact Vista Eyecare to schedule your next eye exam as the first line of defence against vision loss.