Whenever someone asks me which celebrities wear my glasses, regardless of my answers, it always leads the questioner to immediately muse over their own list and top of that list is always Bono.
The U2 front man, never out of the limelight for longer than around 30 seconds, always seems to have a pair of sunglasses adorning his face.
Not a photo opportunity, TV appearance or concert goes by without the energetic pop star wearing a variety of sunnies, and hasn't anyone ever wondered why?
Could it be that he simply likes sunglasses? A sort of serial sunglass wearer? But then it's not just Bono who has this odd habit - it seems to be uniform for rock/pop stars of the past 25 years.
The early years of being a rock legend must be tough on the old complexion and a good pair of shades can work wonders, especially when the stars are dragged on kids' television on Saturday mornings by their pesky record labels.
You can understand why, under the bright studio lights, they might want to slip on a pair of dark glasses to hide the previous hours of debauchery and excess that go with the job.
But this doesn't really excuse the Live 8 headliner and U2 front man who, and let's be honest, is probably past all that now.
So has Mr Bono and his sunglass image just become one? Or is there another possibility for the continued use of the UV protectors by him and his ilk? I propose three different scenarios:
Possible. A rock legend spends many of his or her early years in constant demand and has used the humble sunglass as a shield against the prying cameras, cheeky close-ups and early morning photo calls.
Over the years they get so used to wearing these that they become part of their image and they forget that actually sunglasses are mainly intended for the beach.
Unlikely. Poor old Bono suffers from photophobia and needs to wear sunglasses to keep out the bright flashing lights.
My hypothesis. You're getting on a bit now and let's be honest, you've slipped into that part of the market who need spectacles. Horror of horrors that you should be seen in a little 'over the nose' ready reader. Nope, rock lords do not wear spectacles!
Yes, I am suggesting that the only reason Bono and similar legends seem to live in their sunglasses is because they are really prescription sunglasses, worn instead of spectacles.
Your average super rock god probably last considered spectacles in the early 1980s when national health-style specs were mandatory, Alain Mikli was just bringing out some untameable plastics and the founder of TD Tom Davies was still buying Star Wars figures, so there really wasn't much choice.
Of course none of this is substantiated and Bono is unfortunately not a customer of mine. Perhaps if I put an 8-base blue tinted frame in my next collection... hmmm, it might just work.
- Tom Davies is an eyewear designer and founder of TD Tom Davies. For more details visit www.tdtomdavies.com