No one wants to be put into a box when it comes to most aspects of our lives. And especially not when it comes to sunglasses, which are supposed to be signifiers of individual flair and even, dare we say it, rebelliousness. However, as it turns out, the box is very likely to fit you. Or, rather, rectangular and squarish D-frames are almost universally complementary – no matter your face shape.

Legendary musicians from Roy Orbison and Lou Reed to Bob Dylan have each laid claim to a signature thick, black acetate frame in a D-shaped configuration, so you’re in good company. Scott Walker should also be added to this list – Jacques Maris Mage’s 10th-anniversary Decade Collection features a pair named in honour of the experimental singer (who was thankfully wrong with his proclamation that “the sun ain’t gonna shine anymore”).

This long-standing connection to the glamorous world of celebrity has turned the Wayfarer shape into something of a wearable design icon. But the fact that it’s a fail-safe choice for summer festivals and beach breaks doesn’t hurt, either. And don’t think you have to stick with black – the likes of TOM FORD and Gucci Eyewear champion the style in an eye-catching tortoiseshell, too.

The very first model of sunglasses to be marketed under the Ray-Ban brand name, the Aviator, was designed in the 1930s for US Air Force pilots. Form tends to follow function when it comes to military gear. It’s a principle illustrated here by those signature teardrop-shaped lenses, which were originally designed to protect pilots’ eyes from glare when looking down at their instrument panels, and the slender metal frames, which allowed the sunglasses to be worn comfortably with a flying hat.

The aviator style retains a strong link to the world of aviation – they’re practically standard-issue for commercial pilots – but thanks to the support of Hollywood, and in particular Tom Cruise in Top Gun, they’re now just as popular on the ground as they are in the skies. And for suitably elevated versions of the style, Bottega Veneta Eyewear, Cartier Eyewear and Garrett Leight California Optical are among the other brands to look for.

No, “round framed” doesn’t have to mean perfectly circular. In reality, it’s a much broader term that could describe anything from the vintage sunnies worn by Cary Grant in North By Northwest to the almost goggle-like ones worn by Jean Reno in Léon: The Professional. What we’re really talking about is a lens that’s fuller at the top than the D-shaped lens of a Wayfarer or teardrop-shaped lens of an Aviator.

There’s a certain bookish charm to round frames, and it’s a particularly popular style with vintage-inspired designers. Sister brands Mr Leight and Garrett Leight California Optical offer a great selection of round-framed sunglasses, while SAINT LAURENT and Gucci Eyewear’s version are sure to turn heads.

Roman Emperor Nero was said to have watched gladiatorial bouts through polished gemstones. On the other end of the extravagance scale, specific-coloured lenses and filters are used to treat everything from anxiety and migraines to ADHD and dyslexia, or sensitivity to particular wavelengths of light, making such eyewear a necessity for some. More likely, you might choose to view the world through rose-tinted glasses (or insert tone of favoured outlook – see below). Whichever way, you’re currently spoilt for choice.

Not just in terms of lenses, but also frames. A versatile, resilient material, acetate is naturally transparent, meaning it can be combined with pigments to create a near infinite range of colours. And the likes of LOEWE Eyewear, Bottega Veneta and CELINE HOMME are seeing how far they can push this latter point.

Another consideration: certain lens pigmentations allow the wearer to still be able to see indoors or at night, should that be your jam.

01. Acetate

Acetate, or cellulose acetate to give it its full name, is an organic resin derived from renewable plant sources such as wood or cotton. It’s a powder in its raw state, but it can be melted down and extruded – that means pushed through a nozzle or a metal die – to create acetate sheets, which can then be fashioned into frames.

02. Metal

A trademark of aviator-style sunglasses, metal frames tend to result in a sleeker and more elevated appearance than acetate. Stainless steel is the most commonly used metal, but titanium is popular, too, while precious metals, such as gold or platinum, are generally used as an accent. Solid gold frames are rare due to the difficulty of working with such a dense and soft metal, but you can still buy them – for an understandably high price – from a few high-end jewellery brands.

03. Tortoiseshell

Often seen on the frames of vintage-inspired sunglasses, tortoiseshell acetate has been specially dyed to replicate the distinctive brown, yellow and black markings on the shell of the hawksbill turtle. The real stuff – made of the shells of actual turtles – is now vanishingly rare. Hawksbill turtles were hunted almost to extinction in the 19th and 20th centuries and the trade of their shells was effectively banned in the 1970s.

04. Buffalo horn

A material that was commonly used for frames before the invention of cellulose acetate, buffalo horn is the origin of the term “horn-rimmed glasses”. Still used today by a handful of custom eyewear brands, it’s a sturdy, lightweight, natural material composed entirely of keratin – the same stuff that makes up your hair and fingernails – and it’s known to age beautifully with time.

01. Coloured lenses

Featuring a coloured, translucent finish as opposed to a milky, opaque one, a pair of colourful tinted lenses make a great point of difference amid a sea of black and grey. But they’re not just a style statement, as different colours filter out different wavelengths of visible light. Blue lenses filter out shortwave light, which is known to affect our sleep cycle; yellow lenses improve contrast perception and help concentration.

02. Polarised lenses

Polarised lenses have been treated with a special filter that reduces glare by blocking out light in everything but a certain plane. Think of the filter as a door and the light as a mattress: it needs to be perpendicular to the door in order to pass through. They’re a great choice for watersports or days at the beach, because they reduce the dazzling glare coming off the sea. But be warned: they can also block out the light from your smartphone. (Maybe that’s not such a bad thing.)

03. UV protection

The principal reason we wear sunglasses is the protection that they provide us against harmful UV rays. It’s important to note that this protection isn’t directly related to the tint of the sunglasses; it’s entirely possible for darker sunglasses to offer worse UV protection than lenses with just a light tint. If in doubt, look for claims of UV400 – the number refers to wavelengths up to 400 nanometres, which covers both UVA and UVB rays – and stick to brands that you can trust.

01. A case

Any good pair of sunglasses should come with a protective case. And if it doesn’t come included, buy one. While it might seem like yet another bulky item to carry around, it’s in your interest to do so. Sunglasses are fragile things, and unlike optical glasses, you won’t be wearing them the whole time. When they’re not on your face, they’re in your pocket. And when they’re in your pocket, they're liable to get crushed.

02. A cleaning cloth

Likewise, good sunglasses should also come with a microfibre cleaning cloth. These are designed to clean your lenses with minimal abrasion. This is important, because the coatings on lenses that block out UV or polarised light can be scratched away if you’re not careful.

03. A screwdriver set

The screws fastening the arms of your sunglasses may loosen and need tightening over time. But if you think the Phillips screwdriver from your starter toolkit will suffice, think again. You’ll need a precision screwdriver set instead – they’re widely available and a smart investment.