Getting your vision tested is an important part of your eye health. Optometrists and other eye health professionals can help you identify any changes or problems with your vision and ensure you are getting the support you need. This page summarizes some common vision tests and what they mean.
Vision Australia can support you with vision tests and low vision assessments, as well as answer any questions you have about how vision testing works. You can contact us on 1300 84 74 66 or email info@visionaustralia.org. You can also connect with our services here
Visual acuity tests
Visual acuity tests measure the ability to see fine detail. Visual acuity is determined by measuring the smallest size print that a person can read, both at a distance and close up. In these tests an eye health professional will present different charts or letters to a person.
Distance visual acuity
A visual acuity chart is used to test the clearness of your vision at a distance. For this test a person sits a certain distance away from a chart of capital letters of different sizes and are tested based on the ones they can read.
Near visual acuity
Near visual acuity tests a person’s central vision. This test is performed by reading symbols at a close distance.
Children’s visual acuity tests
Young children’s visual acuity is tested with symbols and pictures. Children who can’t understand these tests are shown different sized stripes.
Visual fields
Visual field tests check peripheral vision. These tests are performed by asking the person to look straight ahead and then changing the position of targets. Visual field tests measure the total area that is seen while the eye is directed straight ahead.
The total visual field with both eyes open is approximately 180° horizontally and 155° vertically. A visual field of less than 60° will start to significantly impact on a person’s ability to move about within the environment. A person must have at least 120° of visual field in the horizontal meridian to legally drive a car in Australia.
Colour vision tests
About 8% of males and 0.4% of females are colour blind. Colour blindness is predominantly an inherited condition, for which there is no cure. Colours may be confused and some colours may be seen more dimly. Some retinal and optic nerve diseases also affect colour vision. Colour vision can affect areas such as career choice and communication.
Testing is done by looking at figures that can only be seen when all the colours can be distinguished. The diagram is an example of an Ishihara colour vision test
Contrast sensitivity tests
Visual acuity measures the ability of the eye to resolve fine detail with maximum contrast (black on white). In real life situations, most tasks are not in black and white and may require the ability to detect small changes in shade. It is useful to determine how much contrast a client requires in order to discern an object from its background. Contrast sensitivity tests use graded levels of grey letters or stripes to determine the lowest difference in contrast discernible. The commonly used tests require the person to indicate which direction parallel lines are facing.
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Contact us early and get the support you need. For more information on Vision Australia’s services call our helpline on 1300 84 74 66 or email info@visionaustralia.org. You can also connect with our services here.