Sunglasses have become essential urban armour. They’re wonderful camouflage for those early mornings when you wish the night before had been different or for those times when you’d rather not let the world know what you’re thinking. They also add instant, if slightly posey, glamour and, on top of all that, there is the medical evidence that in these ozone-thinning days they do an essential job in protecting the retina.

So we need them, we know that, but that doesn’t make choosing them easy. Have you ever watched somebody trying to buy a pair in duty-free (where, I have to confess, I usually end up buying my own)? They take for ever, or at least until the final boarding call, as they whip one pair off and another on. It’s an arduous job — so let me try to simplify this year’s offerings.

First, you need to know that, for real protection, sunglasses should have CR39 lenses, which conform to European Standard. Then you need to decide what you want them to say about you. Funky? You could go the daft route so beloved by the likes of Pixie, Paris and Peaches and go for heart-shaped versions. They can be expensive, £232 for a pair by Moschino, or inexpensive and just as cute from Marks & Spencer for £7.50. However, this is not an option that I’d recommend for anyone over 21.

For those of us who prefer a more grown-up look, it should be glamour, glamour, glamour all the way. At Cutler & Gross they have gone in for Grace Kelly-style allure, with big, over-sized frames in white, black or tortoiseshell. This kind of glamour doesn’t come cheap — they’re £249 — but they do look incredibly chic.

A perfect holiday outfit

I am going on a motorcycle holiday to France and have very little packing space. How do I look chic and crease-free for three weeks? I am 57 and a size 14.

BACKGROUND

• How to choose the perfect sunglasses

• A perfect holiday outfit

• What to buy in the sales

• The 8 trends you should buy in the sales

Live chat: how to dress for not quite summer

Times fashion writer Alice Olins answered readers' questions on what to wear for the British summer

They can be found at net-a-porter.com.

But for real vintage it’s worth reminding you that Cutler & Gross has a shop at Knightsbridge Green, Central London, which is given over entirely to unworn, beautifully preserved vintage glasses.

Nostalgia for glamorous times gone by is evident in most of the fashionable ranges. Retrosun, for instance, is run by Nicole Miller, who has put together a cache of never-used designer sunglasses from the 1970s and 1980s. Being genuinely vintage as opposed to newly-made retro, they have a certain prestige. Most come from extremely distinguished sources — Gucci, Valentino, Christian Dior — and most cost £130 a pair. If, however, you’re after some classic vintage Porsche design folding aviators, they’ll set you back £240. You can buy them from retrosun.co.uk, net-a-porter or my-wardrobe.com.

To check out the current look, let the websites do the editing for you. At Browns (brownsfashion.com) you’ll find a small selection of Linda Farrow’s vintage lines (she was the designer who gave Yoko Ono those amazing visors all those years ago).

Heidi Klein, a trendy boutique that deals mostly in holidaywear and where decisions about which brand to stock are a matter of serious import, has decided this year to sell nothing but Tom Ford’s eyewear.

For those of us who feel uncomfortable wearing anything too groovy and just want something flattering it’s hard to beat grand old classics by Ray-Ban — such as the Wayfarer — and I rather like Persols for men. But if, like many of us, you resent spending a lot of money on something that you just know you’re going to lose, you might like to know that Marks & Spencer has got a splendid line in sunglasses that reflects all the current fashionable styles at user-friendly prices ranging from £5 to £29.50. All have certified lenses. The best are in the Limited Collection range.

For those who really love fashionable eyewear and aren’t averse to a bit of showing off then the current hot number is the Prada butterfly pair as worn by Kate Moss. The black frames have sold out at net-a-porter but you can still get them in pale beige (£190) or tortoiseshell (£175).

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