Hi Graeme! I was starting to feel like I was pushing this thread too hard and now you have made it all worthwhile - THANKS! Lot's of good advice consolidating snippets from elsewhere, adding valuable new info - but most importantly coming from a glider pilot/optometrist.
"Unless your optometrist is made aware of your special needs, you will be unhappy with your new specs". Wow! does this sum up many of our experiences!! I know I'll be armed with a side photo and distances when I next visit an optometrist! "From a personal perspective, I find that lower tech trifocals work well for me, allowing clear distance, intermediate and close vision without any distortion, but some people will find that the simple bifocal will cover all their needs, particularly if they are under 50." Graeme, I am interested to know if it is necessary for the image to 'jump' as it is presented to the eye form one bi/tri region to the next? EG when driving with mine and glancing at the speedometer (which I can read adequately from either lens - but the line seems to fall naturally though the middle . . ) I have to look in 'two different places' as my head moves just a bit. Is this a fact of physics or does the lens maker have control over this sort of thing? Thanks again. Cheers, Jim Kelly ----- Original Message ----- From: "Graeme Thompson" <[EMAIL PROTECTED]> To: "Jim Kelly" <[EMAIL PROTECTED]>; "Discussion of issues relating to Soaring in Australia." <[EMAIL PROTECTED]> Cc: "Discussion of issues relating to Soaring in Australia." <[EMAIL PROTECTED]> Sent: Wednesday, October 06, 2004 10:50 PM Subject: Re: [Aus-soaring] re: Best sunglasses for gliding? Thanks for the welcome Jim. I practice in Sydney and fly at Narromine. You are on the right track when you measured your map & instrument distances. Most refraction (eye testing) is done with the premise that reading is done at 40cm. so the additional power in the lower section of a multifocal is calculated using that distance and the residual focussing ability (accommodation) of the individual's eyes, which decreases with advancing maturity. This is fine for most activities but there are some which don't fit the pattern, particularly some sports and some unusual occupations. Unless your optometrist is made aware of your special needs, you will be unhappy with your new specs. As well as the critical distances you mentioned, the angle of your head relative to the instruments is important. While nothing is as good as having your optometrist measuring everything while you are strapped into the cockpit, a side on photograph will give him (or her) an idea of what you need, how to place the optical centres, and the type of lens which would work for you. Incidentally, the term multifocal means any lens with more than one focal distance, although it is loosely applied specifically to progressive power lenses. >From a personal perspective, I find that lower tech trifocals work well for me, allowing clear distance, intermediate and close vision without any distortion, but some people will find that the simple bifocal will cover all their needs, particularly if they are under 50. If you "must have" a specific tint in your glasses, just like Joe Blow's, try and separate them from Joe long enough to let your optometrist put them in his spectral analyser, if he has one, so that a reasonable match can be obtained. They are not 100% accurate but a darn sight more objective than holding the lens over a bit of white paper. I know that there are other optometrist pilots out there and these are the professionals who will be attuned to your needs as they will have had to solve the problems for themselves. Good luck in your search! Graeme ----- Original Message ----- From: "Jim Kelly" <[EMAIL PROTECTED]> To: "Discussion of issues relating to Soaring in Australia." <[EMAIL PROTECTED]> Sent: Wednesday, October 06, 2004 12:14 AM Subject: Re: [Aus-soaring] re: Best sunglasses for gliding? > Thanks very much Graeme, > > I suspect that you are just one of many lurkers out there!! > > Thanks for your professional comments. > Perhaps you could also be so kind as to point us in the > direction of what questions to ask our optometrist when we next > visit so that we get the best script possible for safety and > success?!! EG I've thought to measure the distance from my eyes > to the panel, and to a map. > Is there a clever way to define the position of the bi/trifocal > edges > from our weird prone seating position?? Etc. > IE How can WE help YOU to get it right?? > > And why not tell us which suburb/city you service? You might > get > an offline email for exact details - it is in all of our > interests to > improve the safety of our sport and an optometrist that knows > our issues has to be an asset! > > Any other professionals lurking out there - please join in - > let's get the facts on the table and wrap up this thread with > some good advice/conclusions and get up there flying again > (with new sunglasses of course) ;-). > > Cheers, > > Jim Kelly > Melbourne. > > > > > > _______________________________________________ Aus-soaring mailing list [EMAIL PROTECTED] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
