On April 20, 2006 I read a post entitled “Progressives for pilots; other questions to ask?” (http://www.optiboard.com/forums/showthread.php?t=16855&highlight=pilot) and prepared a learned dissertation on the subject of eyewear for pilots and other flight deck personnel. Imagine my disappointment when I went to post it and found the thread had been closed. Well if you think I am going to just delete this post you are nuts. Here it is under it’s own thread.
I have been flying since 1955 and have been working in the eye care field since 1969. I have over 7000 hours of flight time both military and civilian. I have a moderate degree of simple hyperopic astigmatism. Until I retired from the eye care vineyard four years ago I have worn every multifocal product on the market. I have found only two solutions to my visual needs while flying and I will confine my remarks to that task only. I will also add that I have presented this solution to many others who I share the air space with and they all agree that this is the best way to go.
First of all, the visual needs on the flight deck/cockpit are quite unique. In particular, all aviators must develop and maintain a scan of the flight instruments without any head movement. Moving the head from side to side or up and down can induce vertigo and possible disorientation which, under instrument conditions can lead to dire consequences. It is quite possible too that body movements may be restricted by seat restraints.
Secondly, there are times when both hands and feet are quite busy and trying to reposition the glasses can really make things interesting.
Third, the environment on each aircraft is different, that is to say, some aircraft have stuff overhead at 12” or down on the deck at 30” and don’t you know, lighting is not always the greatest.
So what conclusions can we draw from these factors? First of all, the flight crew member should have a pair of glasses for each type of aircraft that he flies. And secondly, the lenses are going to have to do all of the work. No repositioning or head movements allowed.
Therefore, to properly fit this eyewear the optician should have the frame that the pilot is going to use with demo lenses installed. He should have a tape measure, a china marker, a roll of electricians tape and, of course, his trusty PD stick. With all of this paraphernalia in hand he should meet the pilot at the airport and proceed to the pilots aircraft.
Have the pilot assume his normal seat position and with his head pretty much stationary in a comfortable and normal position start measuring distances and heights on the demo lenses. I then like to put black electrical tape on the lenses and have the pilot check these heights.
Now, you have to realize that you are not going to find a lens that will meet the requirements of your measurements so you are going to have to make accommodations. These accommodations should be based of flight safety considerations and flight safety alone.
Of prime importance is distance vision. It is the pilots responsibility to see and avoid other air traffic and a mid air passenger exchange followed by aluminum rain can really ruin your day. So, shoot first for unencumbered distance correction from the top of the panel up to the top of the windscreen.
The lens selection for the presbyope will be determined by the pilots degree of presbyopia and amplitude of accommodation. If the pilot can comfortably read a chart or approach plate and see the panel a bifocal is indicated. If a trifocal is indicated select the power of the add to give sharpest vision through the intermediate on the panel – let the reading add “fall where it may” as the panel is more important than the chart. Check this all out under poor lighting conditions as most night flying is accomplished with very dim red cockpit lighting. It there are circuit breakers or any other switches, gauges, dials overhead an occupational bifocal/trifocal will be the lens of choice.
What about tints? This again is an individual decision. You should bear in mind though that frequently we fly in bright sunlight but the panel is in relative shade and can at times be surprisingly dark. And, quite often we find ourselves transitioning from direct sunlight to dense clouds and torrential rains. With this in mind I rule out photochromics. I am also not a big fan of solid tints due to the contrast between high ad low light situations.
Many aircraft have grey polarized sun visors which can offer complete coverage and if the aircraft in question has them I see no point of any further consideration of tints. I personally have a pair of CR39 flat top trifocals in the Meridian (no sunvisor) that I have tinted dark grey from the top of the intermediate on up and clear below that. It works wicked good and every pilot that I meet wants a pair.
I am sure that you have noticed that I have not mentioned progressive lenses. Based on my personal experience and the experience of a lot of flying colleagues these lenses have no place on the flight deck. My spectacle lenses of choice are either flat tops or execs, in glass if you can get them.
What an order. Perhaps Dick has made a mountain out of a mole hill. Many hyperopes are flying around with store bought reading glasses pushed way up high – hey how about a monocle. I have just put down some stuff for you to think about.
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Based on my personal experience and the experience
Originally Posted by rbaker
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