2 totally different axis measurements for same eye?

Discussion in 'Eye-Care' started by Guest, Mar 16, 2006.

  1. Guest

    Guest Guest

    When they use the machine to determine the axis of the right eye, it
    says 165 degrees axis. But when they take me back to do the
    subjective exam, the best results are at 40 degrees.

    Is there some explanation for this? If so, which would be the correct
    axis for the prescription? They wrote me a prescription for 162 axis
    2 weeks ago and I couldn't see through it without rotating the

    So they made a new one with a 174 degree axis, but I can't see clearly
    until I rotate it about 40 degrees clockwise (as viewed by my eye when
    I'm wearing the glasses).

    If I look at an astigmatism wheel chart shaped like a clock, with the
    right eye and no glasses, the clearest line goes from 7:30 to 1:30,
    which is a 45 degree line from lower left to upper right.

    The blurriest line goes from 4:30 to 10:30. which is a 45 degree
    angle from lower right to upper left.

    Where should the axis be?
    Guest, Mar 16, 2006
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  2. Guest

    Dom Guest

    One possible (partial) explanation is if one result was presented in
    plus-cylinder form and the other in minus-cylinder form. In this case,
    the axes should be 90 degrees apart.

    Another possibility is if your cylinder is very low (0.25) then the axis
    result can vary due to measurement error. Theoretically it shouldn't but
    in practice sometimes it does.

    The other possibility is that someone made a mistake! If the subjective
    result was 40 degrees then why did they make your glasses at 162?

    Dom, Mar 16, 2006
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