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Lv 4
? asked in HealthOptical · 8 years ago

How accurate is an auto lensometer?

My eyeglass prescription last year in my right eye is -.75. I ordered glasses. When I went to my eye exam a few days ago, the doctor put my glasses in the auto lensometer and the machine said the prescription was -.50. He retested it several times. Is the machine a little off or was the lens made incorrectly?

1 Answer

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  • Tiger
    Lv 5
    8 years ago
    Favorite Answer

    Well built auto lensometers have an accuracy of +/- 0.25.

    So the error is justified.

    You should never rely upon lensometers to calculate your eye power, accurately. Instead, you should always perform a manual trial and error check with different lenses near an Optometrist.

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