There are many tests that an optician can do to check if a person really needs to
Checking level of vision
A person level of vision is usually checked with the letters chart - these vary in
size and gives the optician an idea if standard of vision is good.
Sometimes a person can have normal sight without correction but they may get symptoms
such as eye strain or headaches. Wearing glasses may ease symptoms.
May need to wear glasses for driving. UK standard is being able to see a number plate
( 2001 plate onwards) from 20m and having a visual acuity of 6/12. If you need to
wear glasses or contact lenses to meet this standard, then it is essential to use
for driving all the time.
For certain occupations, it may be essential to meet certain level of vision, or
it may benefit the person to wear to glasses to make it easier to do tasks.
It will depend on individual circumstances.
Level of vision below standard
During an eye test, the optician may try different lens powers to improve the sight.
There are several scientific methods to obtain these results.
You may be asked to compare two set of lenses or be asked if its better with or without
the lenses, while looking at letters or perhaps circles.
You may be asked questions using several different tests.
Red and Green circles test.
This is called the Duochrome test. It usually has black circles or could have letters/numbers
on red and green/blue bar
The test asks which appear to be more blacker and clearer.
This test allows the optician to fine tune and confirm the spectacle lens power.
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The OXO test.
The optician will put a tinted ( polaroid ) visor over your eyes which will make
things look in 3D and darker.
You will be asked to look at red or green lines next to letter X or another target
- and to see if they are lined up.
This tests if both eyes work together as a team.
Sometimes imbalance between the eyes can cause headaches, double vision or eyestrain.
Can optician check for glasses without asking many questions?
Some patients may be concerned in giving the right answers or find it difficult to
judge. The optician can take account of this and verify results with other tests
that do not rely on answers.
An optician can shine a light onto the eyes using a special instrument called a retinoscope.
The optician is trained to assess the movements of this light and obtain the optical
prescription. There are also automated machines available to do a similar test.
Useful in testing for glasses for babies, young children, adults with speech problems
like after a stroke, in dementia or for persons who have foreign language to the