Aspects of vision – Contrast


Contrast sensitivity and everyday vision

In everyday life you encounter high contrast situations, low contrast situations and everything in between. So loss of contrast sensitivity can have a greater impact on the activities of daily living than the loss of visual acuity alone.
Even in normal lighting situations reduced contrast sensitivity affects how and what you see.

contrast-mounains

If you have normal visual acuity but poor contrast sensitivity you might see the high contrast tree line in the foreground of the picture above yet have difficulty seeing the shapes of the mountains against the sky in the background (low contrast).

Loss of contrast sensitivity – either from aging or eye conditions – can ____ly affect performance of activities of daily living. You may find it challenging to walk down poorly lit stairs.

stairs

You may have difficulty reading a restaurant menu or the newspaper or the label on a medication bottle, seeing road signs or pedestrians while driving at dusk, and even recognizing the faces of people you know in dimly lit settings.

nightdriving

When driving along a poorly maintained road at night, you may wish that the side and center markings were re-striped to enhance the contrast.

nightdriving2

As contrast sensitivity changes, you may find that you see well at one moment and poorly the next. Lighting situations have a strong effect on the vision of the those with low contrast sensitivity. Low light situations – outdoors at dusk or in fog or glare, indoors in poorly lit places – can make you feel you are not seeing well.

Risks!

Reduced contrast sensitivity not only increases inconveniences such as difficulty reading, it also increases your risks of hurting yourself and/or others. Low contrast sensitivity can increase your risk of not seeing a curb or step and falling or not seeing cars and pedestrians when driving in low contrast situations such as dusk or night. .

Acuity and contrast sensitivity

Contrast and visual acuity are not independent. Contrast problems and visual acuity problems can coexist, but one does not cause the other. tbd