Tomey TCP-2000P, Operation Manual

Page: 82 / 113

Operation Manual
82
5.7. Ishihara tests
1. Press to display first Ishihara test.
2. Press Right Arrow to display next test.
3. Press Left Arrow to display previous test.
4. Press Up Arrow to jump 10 tests forward.
5. Press Down Arrow to jump 10 tests backward.
6. Press again, to display test hint.
5.8. Contrast Sensitivity Test
5.8.1. What is Contrast Sensitivity?
Contrast sensitivity is the visual ability to see objects that are not outlined clearly
or that do not stand out from their background. A person with low contrast
sensitivity can have such vision difficulties as:

Difficulties with seeing traffic lights or cars at night

Experiencing tired eyes while watching television

Not seeing spots on clothes or dishes

Not seeing whether a flame is burning on a stove

Needing very bright light to read
5.8.2. Why is Contrast Sensitivity Testing so important?
A lot of people think the popular 20/20 letter chart is the best way to test everyday
vision. Most letter charts, however, only measure a patient's ability to recognize
black letters of different size on a white background, which is a high contrast
situation. But life is also full of low contrast situations. People who have low
contrast sensitivity might be able to read the small letters on a visual acuity chart
but can still have difficulties recognizing objects at night or in a dark room. Unlike
the letter charts, which measure the ability to see objects (or letters) of different