Visual System GM

Implementing Rules (IRs), Acceptable Means of Compliance (AMCs) and Guidance Material (GM) on visual conditions

The following are the requirements for the medical certification of aircrew, including guidance material issued by the UK CAA Medical Department in relation to the visual system

Implementing Rules

Acceptable Means of Compliance

Guidance Material

MED.B.070 Visual System
(a) Applicants shall not possess any abnormality of the function of the eyes or their adnexa or any active pathological condition, congenital or acquired, acute or chronic, or any sequelae of eye surgery or trauma, which is likely to interfere with the safe exercise of the privileges of the applicable licence(s).

Visual System
Refer to Eye Conditions for certificatory guidance on common eye conditions.

Refer to Isotretinoin policy for guidance, where appropriate.

Refer to guidance on Retinal Arterial Disorders and Retinal Vein Occlusion.

Medical reports - Ophthalmic


b) Examination
   (1) For a class 1 medical certificate:
      (i) a comprehensive eye examination shall form part of the initial examination and
be undertaken periodically depending on the refraction and the functional performance of the eye; and
      (ii) a routine eye examination shall form part of all revalidation and renewal examinations.
Class 1
(a) Eye examination
   (1) At each aeromedical revalidation examination, an assessment of the visual fitness should be undertaken and the eyes should be examined with regard to possible pathology. 
   (2) All abnormal and doubtful cases should be referred to an ophthalmologist.  Conditions which indicate ophthalmological examination include, but are not limited to, a substantial decrease in the uncorrected visual acuity, any decrease in best corrected visual acuity and/or the occurrence of eye disease, eye injury, or eye surgery.
   (3) Where specialist ophthalmological examinations are required for any significant reason, this should be imposed as a limitation on the medical certificate.


Eye examination
Refer to Ophthalmology Examination report for Comprehensive eye examination form and guidance on completion.

A routine eye examination that forms part of all revalidation and renewal examinations shall include: history; visual acuity, near and distant vision (uncorrected and with best optical correction if needed), examination of the external eye, anatomy, media, fundoscopy and further examination on clinical indication.

For conditions where deterioration in visual function may pose a significant risk to flight safety, the AMS will impose a RXO limitation

(b) Comprehensive eye examination
A comprehensive visual examination by an eye specialist is required at the initial examination.  All abnormal and doubtful cases should be referred to an ophthalmologist. The examination should include:
   (1) history;
   (2) visual acuities; near, intermediate and distant vision (uncorrected and with best optical correction if needed);
   (3) examination of the external eye, anatomy, media (slit lamp) and fundoscopy;
   (4) ocular motility;  
   

Comprehensive eye examination
Eye specialist is defined in MED.A.010.

Implementing Rules

Acceptable Means of Compliance

Guidance Material

   (5) binocular vision;
   (6) colour vision;
   (7) visual fields;
   (8) tonometry on clinical indication; and
   (9) refraction. Hyperopic initial applicants with an hyperopia of more than +2 dioptres and under the age of 25 should undergo objective refraction in cycloplegia.
(c) Routine eye examination
A routine eye examination may be performed by an AME and should include:
   (1) history;
   (2) visual acuities; near, intermediate and distant vision (uncorrected and with best optical correction if needed);
   (3) examination of the external eye, anatomy, media and fundoscopy;
   (4) further examination on clinical indication.
Class 1
(d) Refractive error
   (1) At initial examination an applicant may be assessed as fit with:
      (i) hypermetropia not exceeding +5.0 dioptres;
      (ii) myopia not exceeding -6.0 dioptres;
      (iii) astigmatism not exceeding 2.0 dioptres;
      (iv) anisometropia not exceeding 2.0 dioptres;
   provided that optimal correction has been considered and no significant pathology is demonstrated.

Refractive Error
Refer to SpecCalc for guidance.
   (2) Initial applicants who do not meet the requirements in (1) (ii), (iii) and (iv) above should be referred to the licensing authority.  A fit assessment may be considered following review by an ophthalmologist.Initial applicants who do not meet the requirements in (1) (ii), (iii) and (iv)
Assessment should be conducted by, or under the supervision of, an ophthalmologist and ensure that there is no underlying pathology or other ocular abnormalities.  Monocular visual acuities shall be 6/6 or better.  Assessment shall include:
   1) Dilated, binocular, indirect ophthalmoscopy in cases of myopia exceeding –6.00 dioptres
   2) Corneal topography at initial assessment (and at renewal where there is significant change in refraction) in cases of astigmatism exceeding 2.00 dioptres.

Implementing Rules

Acceptable Means of Compliance

Guidance Material

   (3) At revalidation an applicant may be assessed as fit with:
      (i) hypermetropia not exceeding +5.0 dioptres;
      (ii) myopia exceeding -6.0 dioptres;
      (iii) astigmatism exceeding 2.0 dioptres;
      (iv) anisometropia exceeding 2.0 dioptres;
   provided that optimal correction has been considered and no significant pathology is demonstrated.
   
Applicants with excess hypermetropia may be assessed by the AMS on an individual basis and should be assessed by a consultant aviation ophthalmology advisor.  Monocular visual acuities shall be 6/6 or better.
Assessment shall include:
   1) Anterior angle assessment, with gonioscopy where clinically indicated, to assess the risk of closed angle glaucoma attack
   2) Fusional reserve testing to ensure there are no adverse prism effects from spectacles
   3) Exclusion of underlying pathology or other ocular abnormalities
   (4) If anisometropia exceeds 3.0 dioptres contact lenses should be worn.
Anisometropia in excess of 3.00D Where anisometropia in excess of 3.00D is found at revalidation, a pilot who does not wear contact lenses should be referred to a local contact lens practitioner for suitability assessment.  A report should be provided after contact lens trial to either confirm successful wearing times and visual acuities or to specify why contact lens wear was not successful.
   (5) If the refractive error is +3.0 to +5.0 or -3.0 to -6.0 dioptres, there is astigmatism or anisometropia of more than 2 dioptres but less than 3 dioptres a review shall be undertaken 5 yearly by an eye specialist.Class 1 Eye Examination Periodicity
Refer to SpecCalc for guidance on comprehensive eye examination periodicity
   (6) If the refractive error is greater than +5 or -6.0 dioptres, there is more than 3.0 dioptres of astigmatism or anisometropia exceeds 3.0 dioptres, a review shall be undertaken 2 yearly by an eye specialist.
   (7)  In cases (5) and (6) above the applicant should supply the eye specialist’s report to the AME.  The report should be forwarded to the licensing authority as part of the medical examination report.  All abnormal and doubtful cases should be referred to an ophthalmologist.In cases of known pathology/abnormality, if there is no change to the condition and the visual standards are met, the indication for and periodicity of further assessment by an ophthalmologist can be determined by the AMS.

Implementing Rules

Acceptable Means of Compliance

Guidance Material


   (2) For a class 2 medical certificate:
      (i) a routine eye examination shall form part of the initial and all revalidation and renewal examinations; and
      (ii) a comprehensive eye examination shall be undertaken when clinically indicated.
Class 2
(a) Eye examination
   (1) At each aeromedical revalidation examination an assessment of the visual fitness of the licence holder should be undertaken and the eyes should be examined with regard to possible pathology.  Conditions which indicate further ophthalmological examination include, but are not limited to, a substantial decrease in the uncorrected visual acuity, any decrease in best corrected visual acuity and/or the occurrence of eye disease, eye injury, or eye surgery.

 
Eye examination
Refer to Ophthalmology Examination report for information for AMEs on completion of the Ophthalmology form.

   (2) At the initial assessment the examination should include: 
      (i) history;
      (ii) visual acuities; near, intermediate and distant vision (uncorrected and with best optical correction if needed);
      (iii)  examination of the external eye, anatomy, media and fundoscopy;
      (iv) ocular motility; 
      (v) binocular vision; 
      (vi) colour vision and visual fields;
      (vii) further examination on clinical indication.
   (3) At the initial assessment the applicant should submit a copy of the recent spectacle prescription if visual correction is required to meet the visual requirements.At the initial assessment
All initial applicants who use optical correction should submit the result of a recent spectacle prescription.
(b) Routine eye examination
A routine eye examination should include:
   (1) history;
   (2) visual acuities; near, intermediate and distant vision (uncorrected and with best optical correction if needed);
   (3) examination of the external eye, anatomy, media and fundoscopy;
   (4) further examination on clinical indication.

Routine eye examination
Refer to Visual Acuity conversion chart for guidance on alternative notation used to record visual acuity measurements

Refer to Visual Acuity revalidation/renewal for guidance on vision and visual acuity measurement at routine eye examinations.

Implementing Rules

Acceptable Means of Compliance

Guidance Material

(c) Distant visual acuity, with or without correction, shall be:
   (1) in the case of class 1 medical certificates, 6/9 (0,7) or better in each eye separately and visual acuity with both eyes shall be 6/6 (1,0) or better;
Class 1
(e) Uncorrected visual acuity
No limits apply to uncorrected visual acuity.
   (2) in the case of class 2 medical certificates, 6/12 (0,5) or better in each eye separately and visual acuity with both eyes shall be 6/9 (0,7) or better.  An applicant with
substandard vision in one eye may be assessed as fit in consultation with the licensing authority subject to satisfactory ophthalmic assessment;
Class 2
(c) Visual Acuity
In an applicant with amblyopia, the visual acuity of the amblyopic eye shall be 6/18 (0,3) or better.  The applicant may be assessed as fit, provided the visual acuity in the other eye is 6/6 (1,0) or better, with or without correction, and no significant pathology can be demonstrated.

(3) applicants for an initial class 1 medical certificate with substandard vision in one eye shall be assessed as unfit.  At revalidation, applicants with acquired substandard vision in one eye shall be referred to the licensing authority and may be assessed as fit if it is unlikely to interfere with safe exercise of the licence held.
Class 1
(c) Substandard vision
   (1) Applicants with reduced central vision in one eye may be assessed as fit if the binocular visual field is normal and the underlying pathology is acceptable according to ophthalmological assessment.  A satisfactory medical flight test and a multi-pilot limitation are required.
   (2) An applicant with acquired substandard vision in one eye may be assessed as fit with a multi-pilot limitation if:
      (i) the better eye achieves distant visual acuity of 6/6 (1.0), corrected or uncorrected;
      (ii) the better eye achieves intermediate visual acuity of N14 and N5 for near;
      (iii) in the case of acute loss of vision in one eye, a period of adaptation time has passed from the known point of visual loss, during which the applicant is assessed as unfit;
      (iv) there is no significant ocular pathology; and
      (v) a medical flight test is satisfactory.
   (3) An applicant with a visual field defect may be considered as fit if the binocular visual field is normal and the underlying pathology is acceptable to the licensing authority.

Substandard vision
Local ophthalmologist reports and an assessment with a consultant aviation ophthalmology advisor will be required before a fit assessment can be made.

Class 1 applicants with substandard vision should be referred to the AMS for further advice about the type of Medical Flight Test to be undertaken.

Implementing Rules

Acceptable Means of Compliance

Guidance Material

Class 2
(d) Substandard vision
   
(1) Reduced stereopsis, abnormal convergence not interfering with near vision and ocular misalignment where the fusional reserves are sufficient to prevent asthenopia and diplopia may be acceptable.
   (2) An applicant with substandard vision in one eye may be assessed as fit subject to a satisfactory flight test if the better eye:
      (i) achieves distant visual acuity of 6/6 (1.0), corrected or uncorrected;
      (ii) achieves intermediate visual acuity of N14 and N5 for near;
      (iii) has no significant pathology.
   (3) An applicant with a visual field defect may be considered as fit if the binocular visual field is normal and the underlying pathology is acceptable.


Substandard vision
UK CAA Sub-standard vision flow chart

Medical Flight Test - Substandard Vision in one Eye

(d) An applicant shall be able to read an N5 chart (or equivalent) at 30-50cms and an N14 chart (or equivalent) at 100cms, with correction, if prescribed.

An applicant shall be able to read an N5 chart
Refer to visual acuity conversion chart for guidance on alternative notation used to record visual acuity measurements.

(e) Applicants for a class 1 medical certificate shall be required to have normal fields of vision and normal binocular function.

Applicants for a class 1 medical certificate shall be required to have normal fields of vision and normal binocular function
Refer to Visual fields and binocular function policy for guidance on normal fields of vision and binocular function.

There is no formal definition available of ‘binocular function’. 


(f) Applicants who have undergone eye surgery may be assessed as fit subject to satisfactory ophthalmic evaluation.
Class 1
(i) Eye surgery
   (1) After refractive surgery, a fit assessment may be considered, provided that:
      (i) pre-operative refraction was no greater than +5 dioptres;
      (ii) post-operative stability of refraction has been achieved (less than 0.75 dioptres variation diurnally);
      (iii)  examination of the eye shows no postoperative complications;
      (iv) glare sensitivity is within normal standards;
      (v)  mesopic contrast sensitivity is not impaired;
      (vi) review is undertaken by an eye specialist.


Eye surgery
Refer to Eye Surgery for guidance

Medical reports - Ophthalmic

Implementing Rules

Acceptable Means of Compliance

Guidance Material

   (2) Cataract surgery entails unfitness. A fit assessment may be considered after 3 months.
   (3) Retinal surgery entails unfitness.  A fit assessment may be considered 6 months after successful surgery.  A fit assessment may be acceptable earlier after retinal laser therapy.  Follow-up may be required.
   (4) Glaucoma surgery entails unfitness.  A fit assessment may be considered 6 months after successful surgery.  Follow-up may be required.
   (5) For (2), (3) and (4) above, a fit assessment may be considered earlier if recovery is complete.
Class 2
(e) Eye Surgery
   (1) The assessment after eye surgery should include an ophthalmological examination.
   (2) After refractive surgery, a fit assessment may be considered, provided that there is stability of refraction, there are no postoperative complications and no increase in glare sensitivity.
   (3) After cataract, retinal or glaucoma surgery a fit assessment may be considered once recovery is complete.


Eye surgery
Refer to Eye Surgery for guidance

Medical reports - Ophthalmic


   (g) Applicants with a clinical diagnosis of keratoconus may be assessed as fit subject to a satisfactory examination by an ophthalmologist.  Applicants for a class 1 medical certificate shall be referred to the licensing authority.
Class 1
(g) Keratoconus
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 ophthalmologist.


Keratoconus
A CCL limitation (‘Correction by means of Contact Lenses only’)  should be applied in cases of keratoconus where the visual requirements are met only with contact lenses, rather than spectacles.

Refer to Eye Surgery for guidance following collagen cross-linking for keratoconus.

Medical reports - Ophthalmic

   (h) Applicants with:
      (1) astigmatism;
      (2) anisometropia;
may be assessed as fit subject to satisfactory ophthalmic evaluation.
h) Heterophoria
Applicants with a heterophoria (imbalance of the ocular muscles) exceeding: 
   (1) At 6 metres:
2.0 prism dioptres in hyperphoria,
10.0 prism dioptres in esophoria,
8.0 prism dioptres in exophoria;
and
   (2) At 33 centimetres:
1.0 prism dioptre in hyperphoria,
8.0 prism dioptres in esophoria,
12.0 prism dioptres in exophoria
should be assessed as unfit.  The applicant should be reviewed by an ophthalmologist and if the fusional reserves are sufficient to prevent asthenopia and diplopia a fit assessment may be considered.

Implementing Rules

Acceptable Means of Compliance

Guidance Material


(j) Spectacles and contact lenses. If satisfactory visual function is achieved only with the use of correction:
   (1) 
      (i) for distant vision, spectacles or contact lenses shall be worn whilst exercising the privileges of the applicable licence(s);
      (ii) for near vision, a pair of spectacles for near use shall be kept available during the exercise of the privileges of the licence;
   (2) a spare set of similarly correcting spectacles shall be readily available for immediate use whilst exercising the privileges of the applicable licence(s);
   (3) the correction shall provide optimal visual function, be well-tolerated and suitable for aviation purposes;
   (4) if contact lenses are worn, they shall be for distant vision,monofocal, non-tinted and well tolerated;
   (5) applicants with a large refractive error shall use contact lenses or high-index spectacle lenses;
   (6) no more than one pair of spectacles shall be used to meet the visual requirements;
   (7) orthokeratological lenses shall not be used.

Class 1
(j) Correcting lenses
Correcting lenses should permit the licence holder to meet the visual requirements at all distances.

Class 2
(f) Correcting lenses
Correcting lenses should permit the licence holder to meet the visual requirements at all distances.


Class 1 & 2 - Correcting lenses
Refer to Guidance on Presbyopic correction for guidance

Refer to Contact Lenses for guidance

Refer to Guidance on Pilot/ATCO spectacle frame and lens choice for guidance

Refer to Guidance on use of Sunglasses by pilots for guidance