Eye Issues / Question
Published: July 15, 2003
Dear TeenHealthFX,
These two questions are about "glasses" corrective eye lenses: 1) What are Trifocals and why do some people need them? 2) What are prisms and why do some people need them?
Signed: Vision & Glasses
Dear Vision & Glasses,
Trifocals are glasses that contain three prescription powers: a distance power, a mid-range power, and a near power. The distance power helps you see things at a distance, the mid-range power helps you see things at normal distances, and the near power corrects your vision for activities that are close. Someone who requires trifocals has to adjust to which part of the lens they should look through for the range of prescription that is needed. Without trifocals, people might have to carry three pairs of glasses and be constantly changing them in order to see clearly at distances.
Prism glasses are prescribed for people who experience double vision or eye gaze disorders. For people who are unable to see the ground due to the fact that their eyes cannot move in a downward direction, prism lens are recommended. They cause the person to feel as though they are walking up him, but often help with balance concerns. People whose field of vision is narrowed can also use prism glasses. The prisms are attached to glasses and they allow the objects in the impaired area to be redirected to the part of the visual field that is working.
For more information on eye health, contact your healthcare provider or ophthalmologist (eye doctor).
Signed: TeenHealthFX
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