Sunglasses in sports

Sunglasses worn by an ocean kayaker

As do corrective glasses, sunglasses have to meet special requirements when worn for sports. They need shatterproof and impact-resistant lenses; a strap or other fixing is typically used to keep glasses in place during sporting activities, and they have a nose cushion.

For water sports, so-called water sunglasses (also: surf goggles or water eyewear) are specially adapted for use in turbulent water, such as the surf or whitewater. In addition to the features for sports glasses, water sunglasses can have increased buoyancy to stop them from sinking should they come off, and they can have a vent or other method to eliminate fogging. These sunglasses are used in water sports such as surfing, windsurfing, kiteboarding, wakeboarding, kayaking, jet skiing, water skiing

and bodyboarding.

Mountain climbing or traveling across glaciers or snowfields requires above-average eye protection, because sunlight (including ultraviolet radiation) is more intense in higher altitudes, and snow and ice reflect additional light. Popular glasses for this use are a type called glacier glasses or glacier goggles. They typically have very dark round lenses and leather blinders at the sides, which protect the eyes by blocking the Sun's rays around the edges of the lenses.

Sunglasses in space

2006: Swedish astronaut Christer Fuglesang wears glasses during a construction mission for the International Space Station

Special protection is required for space travel because the sunlight is far more intense and harmful than on Earth, where it is always filtered through the atmosphere. Sun protection is needed against much higher UV radiation and even against harmful infrared radiation, both within and outside the spacecraft. Within the spacecraft, astronauts wear sunglasses with darker lenses and a thin protective gold coating. During space walks, the visor of the astronauts' helmets, which also have a thin gold coating for extra protection, function as strong sunglasses. Also the frames of glasses in space need to satisfy special requirements. Similar to sports glasses, they should be flexible and durable, and have a reliable fit that can withstand zero-gravity conditions. Some astronauts wear glasses underneath tight helmets and in their space suits, which requires a specially well-fitting frame: Once inside the spacesuit, they cannot touch their heads to push slipped glasses back into place, sometimes for a duration of up to 10 hours while working in zero-gravity. Another risk is that small pieces (screws, glass particles) of the glasses may dislodge and then float into an astronaut's respiratory system. While some of these challenges, especially wearing glasses inside a sunlight-protected spacesuit helmet, may relate to corrective glasses and not necessarily to sunglasses, today NASA uses the same frames for both types of glasses, so that the frames have to withstand all conditions. A related challenge is that even astronauts who do not wear glasses on Earth use corrective glasses in space because zero-gravity and pressure changes temporarily affect their vision; this results in 90 % of astronauts wearing glasses in space, as opposed to 70 % on Earth.

The first sunglasses used in a Moon landing were the original Pilot Sunglasses produced by American Optical. In 1969, they were on board the Eagle, the lunar landing module of the first manned mission to land on the Moon (Apollo 11). – NASA research primarily by scientists James B. Stephens and Charles G. Miller at the Jet Propulsion Laboratory (JPL) resulted in special lenses that protected against the light in space or the light during laser and welding work. The lenses used colored dyes and small zinc oxide particles; zinc oxide absorbs ultaviolet light and is also used in sunscreen lotions. The research was later broadened to further terrestrial applications, e.g., deserts, mountains, or fluorescent-lighted offices, and the technology has been commercially marketed by a U.S. company. Since 2002, NASA uses the frame of the designer model Titan Minimal Art of the Austrian company Silhouette, combined with specially dark lenses developed jointly by the company and "the" NASA optometrist Keith Manuel. The frame is noteworthy in that it is very light, weighing under 10 mg, and contains neither screws nor hinges, so that no small pieces can loosen.

1969 on board the Eagle: Buzz Aldrin stows his sunglasses before the Moon landing

1969: Helmet visor protecting Aldrin's eyes on the Moon