Keratoconus

Guidance for medical examiners when assessing a patient for either a general topic or condition – Keratoconus.

Definition

This guidance should be used for applicants diagnosed with keratoconus by an Ophthalmologist.

Aeromedical implications

Effect of aviation on condition

  • High glare environment may worsen glare and halo formation
  • Low contrast environment at night or in bad weather may significantly impair visual acuity
  • Dry and cold air of aircraft environment may worsen contact lens intolerance

Effect of condition on aviation

  • Impairment of visual function may be safety relevant

Effect of treatment on aviation

  • Complications of chronic contact lens use may contribute to impairment of visual function

Approach to medical certification

Based on the condition

  • Severity of keratoconus
  • Risk of acute visual impairment from acute corneal hydrops
  • Variability of visual function eg acuity instability

Based on treatment

  • Tolerance to treatment
  • Effectiveness of treatment

Demonstrated stability

  • Stable disease during the period of certification
  • Stable response to treatment during the period of certification

Risk assessment protocol - information required

New cases

  • A report from an Ophthalmologist with respect to:
  • Diagnosis
  • History
    • presenting symptoms
    • nature of condition
  • Other relevant medical history (specifically comment on the presence of any of the following)
    • distracting distortions, glare/flare, monocular diplopia or ghost images
    • unstable refraction
    • uncorrectable refractive error
    • contact lens wear complicated by intolerance, allergic reactions (eg, giant papillary conjunctivitis), corneal abrasions,neovascularization
    • significant corneal scarring
    • advanced keratoconus with significant risk of acute corneal hydrops
  • Impairment or loss of function
  • Clinical findings
    • CASA Eye Report, including also
    • retinal examination
    • slit lamp examination
    • corneal topographies (colour copy)
    • contrast sensitivity assessment
    • tolerance of refractive correction
  • Treatment
    • recent past and ongoing treatment must be detailed
    • specify treatment (spectacles, contact lens supervision, cross linking, corneal transplant)
    • comment whether correction can only be achieved with contact lenses
    • ocular and other current and recent past medications (name, dose, start and finish dates, frequency)
    • surgical reports
  • Comment re prognosis and follow up plan.

Renewal

A report from a Designated Aviation Ophthalmologist or Credentialled Optometrist with respect to:

  • Clinical Progress
  • Clinical findings (as applicable):
    • CASA Eye Report also including
    • retinal examination
    • slit lamp examination
    • corneal topographies (colour copy)
    • contrast sensitivity assessment
    • tolerance of refractive correction
  • Treatment:
    • details of any interventions / surgery
  • Comment re prognosis and follow up plan.

Indicative outcomes

  • Review at least annually will be required
  • Return to flying following Collagen Cross Linking:
    • demonstrated stability of refraction is essential
    • full ophthalmological review no sooner than 3 months post-treatment, before consideration of return to flying or controlling
    • due to a risk of corneal haze following this procedure, an assessment is required of contrast sensitivity together with any history of symptoms such as glare, halos or star-bursting before a decision is made to re-certificate.

Favourable

  • Applicants with a clinical diagnosis of keratoconus may be assessed as fit subject to a satisfactory examination by an eye examiner
  • Applicants with keratoconus may be considered for a fit assessment if the visual requirements are met with the use of corrective lenses and periodic review is undertaken by an eye examiner

Unfavourable

  • Distracting distortions, glare/flare, monocular diplopia or ghost images
  • Unstable refraction
  • Uncorrectable refractive error
  • Contact lens wear complicated by intolerance, allergic reactions (eg, giant papillary conjunctivitis), corneal abrasions, neovascularization
  • Significant corneal scarring
  • Advanced keratoconus with significant risk of acute corneal hydrops

Pilot and controller information

  • Keratoconus is an aero-medically significant condition and should be reported to your DAME or CASA on diagnosis
  • Certification is possible in cases where there is stable disease and a stable response to vision correction and treatment
  • A shortened certification period may be required
  • Regular specialist review will be required
  • A condition may be applied in cases of keratoconus where the visual requirements can only be met with contact lenses, e.g. 'Correction by means of contact lenses only'

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Disclaimer

The clinical practice guidelines is provided by way of guidance only and subject to the clinical practice guidelines disclaimer.

Last updated:
Online version available at: https://www.casa.gov.au//licences-and-certificates/medical-professionals/dames-clinical-practice-guidelines/keratoconus
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