A Study to Evaluate the Effectiveness of Critical Flicker Fusion in Distinguishing Different Causes of Altered Vision


  • Study type

  • Study IDs

  • Describes the nature of a clinical study. Types include:

    • Observational study — observes people and measures outcomes without affecting results.
    • Interventional study (clinical trial) — studies new tests, treatments, drugs, surgical procedures or devices.
    • Medical records research — uses historical information collected from medical records of large groups of people to study how diseases progress and which treatments and surgeries work best.
  • Site IRB
    • Rochester, Minnesota: 18-007977
    Sponsor Protocol Number: 18-007977

About this study

The purpose of this study is to evaluate the effectiveness of the critical flicker fusion device in distinguishing different kinds of optic neuropathy and visual perception.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. If you need assistance understanding the eligibility criteria, please contact the study team.

See eligibility criteria

Inclusion Criteria:

  • Patients 4-90 years or older.
  • Patients  with visual acuity between 20/20 and 20/200.

Exclusion Criteria: 

  • Subjects with high standard deviation on the testing, which indicates unreliable results. 


Participating Mayo Clinic locations

Study statuses change often. Please contact us for help.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Cheryl Khanna, M.D.

Open for enrollment

Contact information:

Michael Szewczynski



More information


Publications are currently not available

Study Results Summary

Not yet available

Supplemental Study Information

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