Visual fields should be carried out on Humphrey or Octopus field analysers. To be considered normal, all field tests must show good reliability scores i.e., fields with significant fixation losses or false positives of greater than 30% would be considered unreliable and would need repeating. Monocular Esterman fields are required as the standard test. A binocular Esterman field should be also conducted where there are points missed on the monocular Esterman fields which are not due to normal variations of the blind spot or nasal or brow artifact.
For a monocular Esterman field to be considered as normal, there should be no more than one area with a single missed spot within 20 degrees vertically from the primary position and 30 degrees horizontally from the primary position. A point missed at or next to the blind spot can be accepted provided examination of the optic disc does not show any condition that is likely to jeopardise the safe exercise of the privileges of the licence. Outside the area defined above, there should be no more than a single area of 3 or 4 confluent missed spots or area of loss which exceeds 20 degrees (in any direction). Points missed which could be construed as nasal or brow artifacts can be accepted.
For a binocular Esterman field test to be considered as normal, there should be no more than 3 missed spots, of which not more than 2 shall be contiguous in the visual field defined horizontally by 60 degrees either side of the primary position and vertically by 20 degrees above the primary position and 30 degrees below the primary position.
Where there may be concern of central or paracentral field loss, the CAA may request additional central field test results to be submitted.
Visual fields outside standards in either eye should be considered as ‘substandard vision in one eye’ and certificated accordingly.
In the case of an applicant with a static or congenital visual field loss in one eye, whose central visual acuity is normal in that eye, certification may be considered by the CAA (under the substandard vision algorithm) if the monocular Esterman field of the unaffected eye is normal and the binocular Esterman field shows no more than 2 missed spots in the visual field defined horizontally by 60 degrees either side of the primary position and vertically by 20 degrees above the primary position and 30 degrees below the primary position.
Applicants with potentially progressive field loss will be required to provide periodic visual field test results proportionate to the pathology demonstrated for ongoing certification.
There are three grades of binocular vision in the Worth’s classification: simultaneous macular perception (Grade 1), fusion (Grade 2) and stereopsis (Grade 3). For the purposes of aeromedical certification, ‘normal binocular function’ includes all of these. This would include situations in which individuals have well-adapted heterotropia, are not at risk of diplopia, and/or have adopted a suppression scotoma when both eyes are open.
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