Andrewb wrote:Regarding equipment for flight surgeons a good starting point is finding an appropriate otoscope / ophthalmoscope. If you have access to a WW2 pilots information file there is a basic section covering flight medicine.
Greetings, Andrew! Perhaps I could be of some assistance. I'd like to begin by addressing several of your queries re: eyes, then hopefully get some good information posted later on other aeromedical points of the period. As an aerospace physiologist (and commercial pilot, as well as aviation ground school instructor), I maintain a library of aeromedical documents dating across the span of almost a century.
I have the 1943. 1944 and 1945 editions of the PIF, as well as the counterparts published for navigators, bombardiers (US usage of the term obviously! -- I'm aware that you all in the Commonwealth reserve that title for certain Artillery roles, preferring the title "Bomb Aimer" for those flying in a glass nose for Bomber Command!), and radio observers (wartime euphemism -- actually denoted radar observer). I also have complete copies of medical specialty publications as they pertained to AAF aircrew (e.g.: ophthalmology, psychology/psychiatry, cardiology, etc.). Some of my period files are AAF publications, many others consist of articles from back issues of the professional journal Aviation Medicine
, as well as a few US Navy and foreign sources -- the latter both civil and military.
Please feel free to PM me and I can either post a link or send a file directly. At worst, I could at least assist with locating something appropriate.
Stereopsis -- a/k/a "Depth Perception"
Andrewb wrote:An interesting project would be to research equipment and techniques used for pilot selection screening. There was obviously an importance on visual acuity testing but also there was a lot of apparatus for assessing depth of vision.
Someone here may have information or copies of manuals for flight surgeons.
The Howard-Dolman apparatus was the most common tool used in the American military to assess stereopsis ("depth perception"). An example of this apparatus in use can be observed in a scene from the contemporary John Wayne
film The Flying Tigers
. The Howard-Dolman apparatus fell by the wayside shortly after the war and is no longer in use, as it was shown that it neither revealed a truly accurate assessment of the patient's stereopsis, nor were the standards imposed by any of the services using it ever shown to be anything other than arbitrary
(actually, a lot
of aeromedical standards of that time were arbitrary, yet ended up taking on a sort of "sacred cow" status!).
A number of other tests have come and gone since "The Big One", some better than others, but none truly satisfactory. The post-war Verhoeff test comes to mind as a later test rising to iconic status yet proving to have been a failure. There is one school of thought (and I am in total agreement therewith) which posits that depth perception as it pertains to aviation and the various aircrew roles is a learned
function., not intrinsically inborn
The history of aviation has numerous examples on one-eyed individuals (e.g.: Wiley Post) who performed just fine despite having only one functional eye. Mr. Post, for example, initially learned to fly only after having lost an eye in an oil field accident (the insurance settlement he received from his injury is what paid for his flight training in the first place). In another example of partial monocularity from the other side, Luftwaffe
ace Adolf Galland
had permanently impaired vision in one eye due to glass shards in the orb, received during a pre-war aircraft mishap. He was almost grounded over it.Color perception testing
The AAF used pseudoisochromatic plates (PIP) testing for this during the war. While at least a dozen versions were generally accepted by then, the Ishihara plates -- devised in Japan in 1905 and named for their inventor -- were already the "gold standard" and are still in use as such today. Typically 14 plates are presented, with no more than 2 errors allowed as the pass/fail standard.
Another wartime test devised in 1942 by the US Navy is the Farnsworth Lantern (FALANT) test. Designed to assess whether a partially color-deficient person could still reliably differentiate common signal colors at a functional level, this is the one where the examinee is shown a sequence of presentations of various combinations of red, green and white lamps, shown two at a time. Initially the examinee gets a sequence of 9 presentations, and if he gets all 9 correct, he passes. If not, he gets another sequence of 18 presentations, and can still be passed provided he gets at least 16 correct. Note carefully that he does not
need to perceive red, green or white normally
; he merely needs to be able to consistently tell them apart from each other! Also, during WW2 this test was used exclusively by the US Navy and not
by the AAF. Visual acuity testing
The Snellen chart has been around since its invention in 1862, and the version commonly in use by the time of the First World War is still in use today. A representation of a WW2 era examining station's eye lane would still be proper if one used a currently published Snellen chart. Landolt Rings (these look like a letter "C" of various orientations akin to the so-called "Tumbling E" charts) were devised shortly prior to the war, but were not universally used.
An brief word about visual acuity requirements for the three classes of AAF flying medical examinations of the period....Class I:
This one was required only for applicants to the Aviation Cadet Training Program and for officers and enlisted personnel applying to train in-grade as AAF Pilots, Navigators and Bombardiers (these two only until September 1942, when Aviation Cadet applicants meeting only Class II standard at entry were allowed in on condition that they would only be assigned to Navigator or Bombardier training)., and had to be passed to this standard from the first medical examination until completion of training (what the RAF calls "Wings standard"). Standards of visual acuity were 20/20 or better uncorrected in each eye separately, distant (at 20 ft) and near (at 16 inches). For the Class I of the day, there was also a strict set of limits on refractive error allowed; I need to look back through my references for the exact figures, so I'll get back with an edit here in the near future. Before the war, Gunners and Flight Engineers were also required to meet Class I standards on the first medical exam, although this changed during the war.Class II:
This was required of rated AAF Pilots, Navigators, Bombardiers, and Observers (other than Technical Observers), and of applicants for the Glider Pilot and Liaison Pilot ratings. Prior to September 1942, standards were 20/40 or better uncorrected and correctable to 20/20 or better with spectacles, bilaterally, distant and near. After September 1942, the distant acuity minimum was reduced to 20/100 or better uncorrected, correctable to 20/20 or better bilaterally, again with a spectacle correction.Class III:
This was required of rated Senior/Command Pilots, Technical Observers, Radio Operators, Flight Engineers and Flying Crew Chiefs (after Sep 1942), Flight Surgeons (including pre-war in their case -- one of my texts includes a 1922 photo of a class of Flight Surgeon candidates where nearly half of them are wearing glasses!), Flight Nurses, and Service Pilots*. Original vision standards were an uncorrected distant acuity of 20/100 or better bilaterally, correctable to 20/20 or better bilaterally with glasses, while near vision simply needed to be correctable to 20/20 or better, with no uncorrected minimum specified. No refraction limits were specified. After September 1942, the distant vision standard for Class III personnel was reduced to 20/200 or better bilaterally, correctable with spectacles to 20/20 or better in at least one eye, and to 20/25 or better in the other
A few brief words about the Service Pilot
rating. I'll post something more in-depth about it in the Off-Topic
forum, but since I've touched on that issue, a short explanation here seems appropriate for the readers who may be unfamiliar with it.
This rating applied to male, direct-entry pilots accepted on the basis of having logged at least 300 hours of civilian pilot time, (of which at least 100 had to be on aircraft having a power output of at least 200 brake horsepower) and is not to be confused with the Women's Airforce Services Pilots (WASP) program. These men weren't all necessarily inducted straight from civil life (though some were); many had prior military service within almost every mustering in existence. Some were Regulars, currently serving in other branches of the Army -- officer and enlisted alike -- and happened to have acquired the appropriate civil certifications and experience during their off-duty time. Others were members of the National Guard and the Organized Reserve, again, officer and enlisted alike, while others still were honorably discharged veterans from the interwar era. Some had even seen action in the First
Rather than being trained from (presumably) "zero time" like the Cadets, they were appointed on strength of the qualifications and experience gained in civil life, and were assigned directly to flying duties appropriate to their past experience and training -- typically flying transport missions, ferrying aircraft, or flight instructor duties. Appointment was not
automatic -- several written exams and a flight exam (normally on a BT-series trainer) had to be passed, and each was on probation for his first 90 days. The ones who worked out stayed on and conducted upgrade training on-the-job. For those who didn't, the ones appointed from other Army assignments could usually expect to revert to their previous rank and duty assignment, while the appointees from civilian life were administratively separated, given a railway ticket home, and informed that their local draft boards would be expecting them.
Whereas the women in the WASP program worked for
the AAF, they were not in
the AAF, men accorded the Service Pilot rating were. While WASPs never flew outside the limits of the ATO (ZI and Alaska in most cases), male Service Pilots flew globally, chiefly in ATC and Flying Training Command, although significant numbers made their way into Troop Carrier Command, Air-Sea Rescue and even some of the squadron carrying out antisubmarine duties (until the Navy took over that mission in the latter part of 1943). These men outnumbered the WASPs by approximately 11 to 1, comprised the vast majority of ATC pilots and an estimated 40% of Troop Carrier pilots (an unknown portion of whom may also have gotten there by volunteering for glider duty). After one year of active duty as a Service Pilot, it was possible under the regulations of the period to "re-rate" to Pilot, provided one met Class II standards (or could be waivered thereto; this was not always approved, but did occasionally happen). Further, commissioned officers holding only the Service Pilot rating were still eligible to command certain flying units: those equipped exclusively with aircraft of the C-, G-, L- and/or U-series only. I'd like to post more detailed historic information about the Service, Liaison and Glider Pilot ratings, however I'm going to post that on the "Off-Topic" forum.