• Why would an eye chart exam be done after eye dilation?


    Question:

    Why would an eye chart exam be done after eye dilation?


    Answer:

    Visual acuity (the sharpness of vision) is usually measured as the first part of an eye examination. If you normally wear glasses or contact lenses, your vision will be checked with these lenses. Your distance vision may also be checked without lenses to see if you meet the criteria in your state to drive without corrective lenses. Visual acuity is checked using the distance eye chart and a near (reading) card. A refraction may be done to see if your vision can be improved with a change in your lenses.

    Vision may be checked again after dilation if your pupil is extremely small or if there is cloudiness in your cornea or lens that might block your vision with a normal size pupil. A refraction may also be repeated after dilation to confirm your glasses prescription. Certain dilating drops temporarily paralyze your focusing muscles so your ophthalmologist can more accurately determine how much glasses correction you need. This is called a “cycloplegic refraction” and is frequently necessary in children and young adults.


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