Sunglasses

For most outdoor use, yes. Polarised lenses block the horizontal glare that bounces off water, wet roads, sand and car bonnets, so you see more clearly with less squinting and eye strain. That makes them ideal for fishing, boating, driving and the beach. The trade-offs are that they can make some phone and dashboard screens harder to read, and some skiers prefer non-polarised lenses to spot icy patches.

UV400 means the lenses block ultraviolet light up to a wavelength of 400 nanometres, which covers both UVA and UVB rays. That protects your eyes from sun damage that can contribute to cataracts and other problems over time. Quality sunglasses from established brands provide full UV protection, but cheap or fashion lenses may not, so always check for UV400 or 100 percent UV protection on the label.

Sunglass lenses are graded by how much light they let through. Category 0 and 1 are clear or lightly tinted for low light, category 2 suits moderate sun, and category 3 is the most common general-purpose sunglass for bright New Zealand days. Category 4 lenses are very dark, for glaciers and high alpine sun, and are not suitable for driving. Most fishing, sport and lifestyle sunglasses are category 2 or 3.

Glass lenses offer the sharpest optical clarity and are very scratch resistant, which is why many fishing sunglasses use them, but they are heavier and can break on hard impact. Polycarbonate lenses are lighter, more impact resistant and safer for sport, though they scratch more easily. Choose glass for the clearest view on the water and polycarbonate for running, cycling and active use.

Grey lenses reduce brightness evenly and keep colours natural, making them the best all-rounder for driving and bright days. Brown, copper and amber lenses boost contrast and depth perception, which helps on the water and in changing light. Green lenses balance contrast and natural colour, and mirrored coatings cut extra glare in very bright conditions. Many brands also offer contrast-enhancing lens technologies.

Sunglasses should sit comfortably on your nose without pinching, with the arms resting lightly over your ears and not pressing on your temples. Your eyes should sit roughly in the centre of the lenses, and the frame should not slide down when you look down or move your head. Wraparound frames block more light from the sides, which helps on the water and for sport. Trying several frames is the best way to find your fit.

Many performance frames from brands like Oakley and Costa can be fitted with prescription lenses, but this is usually done through an optometrist rather than off the shelf. If you need a prescription, check with your optometrist which frames and lens types suit your eyes before you buy. Some people also wear contact lenses with standard sunglasses, which gives the widest choice of frames.

Rinse the lenses with fresh water first to wash off salt, sand and grit, which cause most scratches. Then clean them with a drop of mild soap or lens cleaner and dry with a soft microfibre cloth. Avoid paper towels, clothing and your shirt tail, which can scratch coatings. Store your sunglasses in their case rather than loose in a bag or on the dashboard, where heat and knocks damage lenses.