Common conditions

How eye tests work

If you want to protect your eyesight, regular eye checks are a must.

Fit&Well magazine
December 2015

Our eyes allow us to read a book, enjoy the beauty of a sunset and see the people we love “so it’s important to have them checked regularly so that any issues can be detected and treated as early as possible”, says Margaret Knapman, Managing Optometrist at HCF Eyecare Associated Optometrists.

Making your appointment

When you ring to book in for an eye exam, make sure you mention family history (of glaucoma, for example) or health conditions (such as diabetes) that may indicate you need a longer appointment.

Pre-test consultation

The optometrist asks questions to clarify the main reasons for your visit (if you’re experiencing headaches or blurred vision, or simply want an eye check-up).

Your eye check

In the consulting room your optometrist will conduct some or all of the following eye checks:

Visual acuity test
With one eye covered, you read letters of the alphabet from a chart, with the type getting smaller with each row. This measures your sharpness of vision.

Slit lamp check
A special microscope with a strong light illuminates the structures of your eye to allow assessment of your eyelids, lashes, irises, corneas and eye lenses.

Eye function tests
The optometrist tests your muscle function, eye coordination and peripheral vision by getting you to visually track a moving object, look at a distant target and by bringing objects or computer images into your line of vision.

Glaucoma screening
Glaucoma causes a build-up of pressure in your eyes that damages the optic nerve. Tests for the condition include an optic nerve examination. During an optic nerve examination the optometrist may use pupil-dilating drops (which take about 20 to 30 minutes to work) and a small instrument called an ophthalmoscope to examine the optic nerve. 

“As your vision may be affected for an hour or two after the test, you will need to catch public transport or have someone else drive you home,” Knapman says.

For the tonometry (or ‘puff of air’) test a small puff of air is directed into each eye. “The faster the return speed of the air, the higher the pressure, which may indicate risk of glaucoma,” she explains.

Refraction test
If you need or use glasses your optometrist will ask you to look through a series of different lenses and pick which one looks clearer to determine the most appropriate lens power. The prescription is handed to an optical dispenser who helps you choose your glasses frames and arranges for them to be made up with the prescribed lenses. This may take a few days or weeks.

Retinal photos
While you look through an eyepiece that resembles a pair of binoculars a digital photograph is taken of one eye, then the other. “This high-resolution image is uploaded onto a screen,” says Knapman.“It allows your optometrist to view the back of your eye, including your retina, optic nerve and blood vessels, to check for signs of eye issues such as macular degeneration, cataracts, glaucoma and impacts of high blood pressure.”

More for Eyes

You could get 100% back on a range of prescription glasses and digital retinal imaging through our More for Eyes program.

Related articles


Eyes can give doctors valuable insights into a range of potentially dangerous health conditions.


Your guide to staying on top of your health, through every stage of life.


Maximising your time with your doctor can bring real health benefits.


Many serious conditions have vague or hidden symptoms. Here’s how to identify and screen for them.


This communication contains information which is copyright to The Hospitals Contribution Fund of Australia Limited (HCF). It should not be copied, disclosed or distributed without the authority of HCF. Except as required by law, HCF does not represent, warrant and/or guarantee that this communication is free from errors, virus, interception or interference. All reasonable efforts have been taken to ensure the accuracy of material contained on this website. It’s not intended that this website be comprehensive or render advice. HCF members should rely on authoritative advice they seek from qualified practitioners in the health and medical fields as the information provided on this website is general information only and may not be suitable to individual circumstances or health needs. Please check with your health professional before making any dietary, medical or other health decisions as a result of reading this website.