This is an interesting situation. Short version is it looks like you could fly under a medical certificate after an adjustment period, or under BasicMed if your physician is willing to sign off. Obviously there's a lot of details. Particularly about vision in the other eye.
There aren't any vision related 1 time SI provisions for BasicMed. The CMEC just requires the physician to examine the function of the eyes and vision without much direction on specific criteria:
"4. Eyes (general), ophthalmoscopic, pupils, (equality and reaction), and ocular motility (associated parallel movement, nystagmus):"
"20. Vision: (distant, near, and intermediate vision, field of vision, color vision, and ocular alignment)"
The "BasicMed Section 3: Instructions for State-Licensed Physician" states:
"As the examining physician, you are required to:
1. Review all sections of the checklist, particularly SECTION 2 completed by the airman.
2. Conduct a comprehensive medical examination in accordance with the checklist by:
a. Examining each item specified;
b. Exercising medical discretion, address, as medically appropriate, any medical conditions identified; and
c. Exercising medical discretion, determine whether any medical tests are warranted as part of the comprehensive medical examination.
3. Review and discuss all prescription and non-prescription medication(s) the individual reports taking and any potential to interfere with the safe operation of an aircraft or motor vehicle.
4. Complete the Physician’s Signature and Declaration.
5. Complete the Physician’s Information."
So technically you could be legally blind, and if you meet all the other criteria for BasicMed and a physician signs off, you're legally good to go under BasicMed. Obviously this wouldn't be a good idea as the self certifying provisions of the FARs are a factor. The Guide for Aviation Medical Examiners has more specific guidance regarding monocular vision, which would be at the extreme end of losing sight in one eye. This would be related to flying under a medical certificate rather than BasicMed. Here's the guidance:
"Monocular Vision. An applicant will be considered monocular when there is only one eye or when the best corrected distant visual acuity in the poorer eye is no better than 20/200. An individual with one eye, or effective visual acuity equivalent to monocular, may be considered for medical certification, any class, through the special issuance section of part 67 (14 CFR 67.401).
In amblyopia ex anopsia, the visual acuity loss is simply recorded in Item 50 of FAA Form 8500-8, and visual standards are applied as usual. If the standards are not met, a Report of Eye Evaluation, FAA Form 8500-7, should be submitted for consideration. Although it has been repeatedly demonstrated that binocular vision is not a prerequisite for flying, some aspects of depth perception, either by stereopsis or by monocular cues, are necessary. It takes time for the monocular airman to develop the techniques to interpret the monocular cues that substitute for stereopsis; such as, the interposition of objects, convergence, geometrical perspective, distribution of light and shade, size of known objects, aerial perspective, and motion parallax.
In addition, it takes time for the monocular airman to compensate for his or her decrease in effective visual field. A monocular airman’s effective visual field is reduced by as much as 30% by monocularity. This is especially important because of speed smear; i.e., the effect of speed diminishes the effective visual field such that normal visual field is decreased from 180 degrees to as narrow as 42 degrees or less as speed increases. A monocular airman’s reduced effective visual field would be reduced even further than 42 degrees by speed smear.
For the above reasons, a waiting period of 6 months is recommended to permit an adequate adjustment period for learning techniques to interpret monocular cues and accommodation to the reduction in the effective visual field.
Applicants who have had monovision secondary to refractive surgery may be certificated, providing they have corrective vision available that would provide binocular vision in accordance with the vision standards, while exercising the privileges of the certificate. The certificate issued must have the appropriate vision limitations statement."
The good news is it doesn't sound like monocular vision in and of itself is completely disqualifying. Interested in seeing how the AMEs on the board opine.
