Re: [aus-soaring] Best sunglasses for gliding ?

[Jim Kelly]

No problem from me, Terry. If it all helps us fly safer then that's excellent. It would be great if a professional would jump in and add their comments in case some of this info is misguided . . . Glad you found a thorough opto. The last couple have been way too hurried for my liking . . .   And, what was the 'fields test' comprised of Terry?   Cheers,   Jim         ----- Original Message ----- From: Terry Neumann To: Jim Kelly ; Discussion of issues relating to Soaring in Australia. Sent: Thursday, September 30, 2004 11:22 AM Subject: Re: [aus-soaring] Best sunglasses for gliding ? My thanks to Jim and Brett for most enlightening contributions on graduated lenses. I specifically mentioned the requirement for gliding when I was getting the current set of glasses/spectacles, and my opto made some pertinent comments on what the special requirements might be, but I didn't come away with the fine detail which Jim and Brett mentioned. However, I was most impressed with his thorough attention to detail.   He suggested I have a "fields test" - an interesting exercise - which confirmed that my peripheral vision was still quite ok.  (significant sigh of relief at this finding) I will probably get a "backup set" made in the near future.  If I may, I'll show him copies of your contributions for his consideration. Thank you again, Terry Jim Kelly wrote: >>graduated ones with polarizing magnetic clip-ons <<   Interesting notes Terry. I have tried a similar setup but one of our club members warned us of a significant danger in graduated lenses for gliding . .   In his considered opinion we should have a driving/gliding prescription made to give 'exact focus at infinity with the eyes at rest' to see those vital threatening specs during lookout, not to mention dust and birds that mark the thermals! A graduated lens apparently does not do this well as you cannot rely on your eyes always being focussed at infinity.   Now, having the 'focus at infinity with the eyes at rest' means that our short vision is poorer than normal - being exacerbated by the main lens being set longer than for normal civilian use. This means that a (narrow) bi-focal region is usually needed - focussed to see maps and instruments at arms length (perhaps 300 to 800mm?).   Perhaps I can try to explain further. If the opto does his normal job he will choose a lens that works fine at (guessing the numbers here) 20m and infinity, but is actually best at 200m and 'pretty good' at 20m and infinity. David suggests that the sweet spot should be at infinity, not 200m. Thus the lens might work 'pretty well' from say 50m to beyond (!) infinity but is actually perfect at infinity, thus making a greater need for bi-focal or even trifocals. My first set made like this have been great although the bifocal part is too wide and next time I'll get it made to '28' not '35'. Looking forward to the benefits of polarizing too.   I've also been contacted offline by a fellow pilot been using such a setup for years - no worries.       >>It would be interesting to know if  it's possible to get "clear", that is non-tinted polarizing glasses (or clip-ons) as used in photographic polarizing filters<< What a great idea Terry!   This has been a most interesting thread, I hope that we all get to benefit in the air! Thanks to all for your valuable contributions.   Cheers,   Jim Kelly         _______________________________________________ Aus-soaring mailing list [EMAIL PROTECTED] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [EMAIL PROTECTED] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring

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