Heterophoria portion of FAA Eye Exam for Pilots Seeking Medical Certification

Item 54: Heterophoria

Apr 2014

Abbreviated Briefing:

Class 1 and 2 Limits

  • 1 Prism Hyperphoria
  • 6 Prisms Esophoria or Exophoria
  • Strabismus or diploplia (double vision) require deferral

Class 3 Limits

  • No specific heterophoria limits
  • Strabismus or diploplia (double vision) require deferral



Guidance is compiled and interpreted by professional pilots and physicians at FlightPhysical.com from the 2014 AME Guide pages 178-180, FAA and FDA web data (www.FAA.gov & www.FDA.gov), instructions specified in the Aeronautical Information Manual, Federal Air Surgeon Bulletins from 1999-2015, and 14 CFR Part 61 and Part 67 (the FARs).

Sample Response Grid that AME will Use
54. Heterophoria 20’ (in prism diopters)
Esophoria Exophoria Right Hyperphoria Left Hyperphoria

I. Code of Federal Regulations

  • First and Second-Class Legal Standards: 14 CFR 67.103(f) and 67.203(f)

    (f) Bifoveal fixation and vergence-phoria relationship sufficient to prevent a break in fusion under conditions that may reasonably be expected to occur in performing airman duties. Tests for the factors named in this paragraph are not required except for persons found to have more than 1 prism diopter of hyperphoria, 6 prism diopters of esophoria, or 6 prism diopters of exophoria. If any of these values are exceeded, the Federal Air Surgeon may require the person to be examined by a qualified eye specialist to determine if there is bifoveal fixation and an adequate vergence-phoria relationship. However, if otherwise eligible, the person is issued a medical certificate pending the results of the examination.

  • Third-Class Legal Standards (14 CFR 67.303(f))

    Third-Class Pilots: No Standards (Not Measured)

II. Examination Equipment and Techniques


  1. Red Maddox rod with handle.
  2. Horizontal prism bar with graduated prisms beginning with one prism diopter and increasing in power to at least eight prism diopters.
  3. Acceptable substitutes: any commercially available visual acuities and heterophoria testing devices.

Note: There are specific approved substitute testers for color vision, which may not include some commercially available vision testing machines. For an approved list, See Item 52. Color Vision.

Examination Techniques:

Test procedures to be used accompany the instruments. If the Examiner needs specific instructions for use of the horizontal prism bar and red Maddox rod, these may be obtained from a RFS.

III. Aerospace Medical Disposition

  1. First- and second-class: If an applicant exceeds the heterophoria standards (1 prism diopter of hyperphoria, 6 prism diopters of esophoria, or 6 prism diopters of exophoria), but shows no evidence of diplopia or serious eye pathology and all other aspects of the examination are favorable, the Examiner should not withhold or deny the medical certificate. The applicant should be advised that the FAA may require further examination by a qualified eye specialist.
  2. Third-class: Applicants for a third-class certificate are not required to undergo heterophoria testing. However, if an applicant has strabismus or a history of diplopia, the Examiner should defer issuance of a certificate and forward the application to the AMCD. If the applicant wishes further consideration, the Examiner can help expedite FAA review by providing the applicant with a copy of FAA Form 8500-7, Report of Eye Evaluation.

Related Pages:

This page discussed the Heterophoria portion of the Eyes & Vision section of the Fight Physical Examination required of pilots.

Reminder: use FlightPhysical.com to familiarize yourself with aviation medical regulations and guidelines, but always discuss your specific situation with one or more AMEs before dedicating resources toward expensive clinical workups. Find an AME now