/ /

  • linkedin
  • Increase Font
  • Sharebar

    Postop keratometry not associated with night-vision problems

    Effect was predictor of satisfaction, change in halo; but not glare, starburst, ghosting/double vision


    “We can explain about 20% of the reasons why patients are dissatisfied,” Dr. Schallhorn said. “However, we cannot explain fully 80% of the variance of why patients are dissatisfied.”

    In this study, the researchers did not try to find a cutoff point for postoperative keratometry beyond which patients should not be treated. Because of concerns about excessive flattening, many clinicians have used a borderline of 34 D.

    Related: Using femtosecond lasers in eyes with previous surgery

    Only 7 patients in this sample had corneas flatter than that. All of them were “very satisfied” or “satisfied” with their visual outcomes and did not report night-vision problems. However, the number was too small for the researchers to draw statistically significant conclusions about this group.

    The researchers acknowledged some other limitations in the paper.

    Most important, it was retrospective. Retrospective studies are more susceptible to biases, such as selection bias, that are outside the control of the researchers, he noted.

    Another weakness is that the researchers used an automated device to measure the keratometry. Also, the number of patients who have severe and significant problems is not high, making them hard to study. And symptoms tend to get better with time.

    Editorial: Ten-day workweek for ophthalmologists

    “On the other hand, the sample size is enormous and that allows a huge amount of statistical power in being able to analyze the data and subgroups within the population,” Dr. Schallhorn said.


    Steven Schallhorn, MD

    E: [email protected]

    This article was adapted from Dr. Schallhorn’s presentation at the 2016 meeting of the American Academy of Ophthalmology. Dr. Schallhorn is a consultant for Abbott, AcuFocus, and Carl Zeiss Meditec, and chief medical director of Optical Express.

    New Call-to-action


    New Call-to-action


    You must be signed in to leave a comment. Registering is fast and free!

    All comments must follow the ModernMedicine Network community rules and terms of use, and will be moderated. ModernMedicine reserves the right to use the comments we receive, in whole or in part,in any medium. See also the Terms of Use, Privacy Policy and Community FAQ.

    • No comments available


    View Results