My remarks about sunglasses at #09 were general. Agree that with aviation, mountain climbing and tramping to the poles etc they can be essential. 90% of people 'in the street' wear them for 'style'.
"The point I was rabbiting on about at #08"
Which I have just read and totally agree with.
Peter I have something pretty close to what Bathman shows in post #18. Custom made. They are graduated from top to bottom, whereby the top is relatively dark and the bottom almost clear - windshield vs. panel. It took a while to get them right (I had them designed by an optician in Spain, but they were made by a factory in France and it appeared that these guys just thought the high and large 'near' inset was in the wrong place), but they work a treat. Cost, IIRC, was around EUR 200-300 for the lenses, I had them fitted into Aviator frames which I had.
An interesting approach to glasses (spectacles)
When one gets “old” (I am 56 
) one usually has the problem that glasses are needed for flying, but one can’t use the same lens for all of
Obviously there is a well known solution: bifocals. But a lot of people – myself included – don’t like the idea of having to continually move one’s head up and down to get the focus. Also the older you get the greater the variation that is required, to cover both 1 and 3.
One very clever optician showed me a good solution. It assumes a combination of these:
This leads to an interesting solution, which is use the long distance prescription on the dominant eye, then back off a bit for the other eye so the instrument panel is on focus (but no more than another 0.50 dioptre or so).
The terminal chart reading requirement is then easily solved with a little reading insert at the bottom of the lenses; typically this is about +1.25 or so for that distance. That is the net figure so that if e.g. you have -0.5 for distance the required “reading glass” insert will be 1.75 (but every optician knows that).
The result takes a couple of minutes to get used to, and then you have perfect vision.
If the difference between the two eyes feels too great, a further approach makes use of the rather controversial assertion that you don’t need absolutely perfect long distance eyesight for flying (like you do need for e.g. reading roadsigns when driving). You back off a tiny bit on the long distance prescription on the dominant eye – maybe by 0.25 – and this reduces the difference. Having the instrument panel out of focus at all is not an option, and one needs to be able to read the altimeter settings on both altimeters (LHS and RHS). It is controversial but, frankly, somebody whose “full” long distance prescription is -0.25 will easily pass the Class 1 CAA and FAA medical without glasses, and many will pass it at -0.50 without glasses. So this is really no big deal, IMHO. Such a small back-off reduces the difference between the two eyes that’s needed to keep the instrument panel in focus. I am not sure I would be doing this for night flight, however, because the eye aperture is much larger.
However – I am told that the above is illegal in the UK. The CAA disallows e.g. the use of two different contact lenses in the two eyes (one for long distance and one for reading) and the above amounts to the same thing. However, what I describe above is nowhere near that extreme; having a reading lens on the non-dominant eye would make that eye useless for distance and would feel very weird.
However – I am told that the above is illegal in the UK.
Everywhere, I’m afraid… What you describe has always been my natural “outfit”. One of my eyes is slightly myopic the other one slightly hyperopic. Which means that – without glasses – I can both see well in the distance and in the near field. There is even a zone (size depending on lighting conditions) where I can see three dimensional (which has been a slight problem during my medicals when stereo vision was still tested). This works fine as long as both eyes are “working”. And this is why I never wore/wear glasses for daily life. But I have to wear them for driving and of course for flying too because the requirement is the ability to see near field and distance with only one eye alone. So I’m afraid your asymmetric solution will not get approval.
Why not consider varifocals? I have been using them for the last 15 years. You need an adaption phase of 10-14 days, which is not too critical (mind the stairs downwards),
but then you feel like having again 100% eye-sight (twenty-twenty vision)
I am not that much younger than you, Peter, and have the same problem.
I have spoken with my AME about it, spoken with my optician and I have just started using varifocals designed to be worn so I can see over the top for distance, through the top of the lens for instrument panel (only really need them for reading the baro scale) and through the middle for the charts on my lap (and through the bottom of the lens for close work). So far, so good.
Someone said it was old age but I don’t think I am old yet, maybe in another 50 years I will.
I tried the “approved” solution and spent a vast amount of money on “executive bifocals”
and while these work fine for driving (where the only “job” is getting the line positioned to coincide with the top of the dash) they don’t work for me for flying because
Obviously one can “make it work” like one can make anything work if pushed, but I didn’t consider it satisfactory. One can also get around #2 by flying UK-PPL-style B52 circuits…
There may be a solution for #2 which extends the upper lens to the bottom left corner but I couldn’t find anybody who wanted to do it and anyway I wasn’t going to spend another 500 quid on testing. I already have enough useless-for-flying glasses in the car
I found Specsavers brilliantly helpful.
They gave me a “blank” pair of glasses for me to take to try out in the aircraft and to mark where I wanted the dividing line for the Executive Bi-Focals. I marked it for the top of the instrument panel/cowling. They made 2 pairs, 1 clear and one dark grey smoked “sunglasses”. One pair came back with the line slightly too high so they remade them for nothing. They work a treat and I will now get a brown smoked pair which will be great for bright but cloudy days.
At 72 I’ve been wearing bifocals for several years, and have no problems with them for driving, flying, or reading/computer. (My first attempt at landing resulted in a go-around while I figured things out – I lost the ground at round-out.) I don’t yet wear them for walking yet – when I used the prescription sunglasses I found rough ground very difficult.
