Personally, I'm relatively specs blind - I don't notice them unless there's a lot going on: exaggeratedly large or small frames; or a great deal of surface decoration, as in Dame Edna's eyewear or those post-Versace things with coin-studded arms. But be assured, people do notice and spectacles can make big and distracting statements that you might not intend.
Over the past 15 years, design has become the big issue in the opticians' world. It's the way they distinguish themselves and the way they create added-value. Wherever you go, there'll be fancy frames, fancy names and fancy prices too. All the big design houses see eyewear as another profit stream, so you're being sold into an aesthetic when you're down there to see if your prescription needs changing. Watch out.
And the aesthetic has changed, utterly. Because contacts are usual not exotic, specs themselves have become a back-up for many management types, hence the emphasis on frames. And - like it or not - frames have been fashionised through three or four major fashion cycles in the past 20 years. You could find yourself in the position of a mid-thirties broker I know who's invested in a high-style, high-tech pair (small, wire-framed, designer SS look) that puts his whole comfortable Sloane dress code in jeopardy. It jars horribly and I felt like asking him if adultery or a move to a creative industry job was imminent.
In fact he'd bought for the most conservative of reasons - namely that, not being eyewear-literate, he'd chosen the 'plainest' pair in the shop.
He didn't know that designer-types with black linen suits and a feeling for the minimal had been wearing that sort of thing since, oh, about 1985.
Of course he'd rejected the raspberry jelly early '80s Buggles/Timmy Mallett frames. He knew serious people didn't wear those, nor the over-decorated Mafia-look things. But he'd ended up with an equally disconcerting statement.
Another friend lurched into the modern world (10 years ago he looked like Hugh Grant) by stages. He started with contacts to replace his horn-rimmed fogey look, then gradually moved from a Merchant Ivory wardrobe to a modern European one. Off came the centre-parted flop, replaced by a number-two crop. But the horn-rims were kept for emergencies; and they looked very odd on the 'new' Robert.
Big eyewear fashions, such as huge aviators or tiny granny specs, are actually very period-specific, very group-specific. They date your affinities and your heroes instantly. But if you want to declare for John Lennon you'd better do it knowingly.
My spies tell me that the mainstream, OK norm, now is based on thin, light, metal frames, with vision-shaped lenses covering the vision area without swamping it or screwing into the eye socket.
The current favoured mainstream shapes are flattish ovals and, more recently, 'soft rectangles'. (Too rectangular and you're a fashion victim - but, stop press, Boris Johnson, the new Spectator editor, has recently adapted this style, so it's safe enough for you.)
Frame finishes and materials are self-effacing. Bright gold is ageing and uncool. Heavy black frames make too much of a statement now - if you're Clark Kent, deceptively studious, you shouldn't be advertising it.
Bright colours are for creative types only. Tortoiseshell is nice in moderation combined with a modernish frame-shape. At one media business party I went to recently, the girls (sharp suits, not creatives) started comparing specs, and they'd all got this tortoiseshell-framed softened rectangular style. So they started checking out the boys (late-thirtysomethings) and most of them had them too.
The best, most original version of this 'modish' style came from Cutler and Gross, whose founder Tony Gross is a dedicated eyewear designer with a sophisticated view of tribal eyewear codes.
But as well as fitting all the appropriate tribal codes and matching your wardrobe, your specs also have to fit you. They're very intimate appliances, jammed round your head, and their size, colour and weight have to work with your size, colour and weight. You need advice about how they look on you - and not just from the optician. You need a friend on hand when you're buying specs, someone who knows your work and knows your face.
And you need to take your time - certainly more than you'd take to decide on a ready-made suit - because you're going to wear them 10 times as long.