Not for imperial gleam did the two Apollo 11 astronauts who walked on the moon wear glass visors surfaced in gold.
Their hands were pressed to the glass like visors as they talked excitedly about what they saw inside, as if something marvellous were moving through the aisles.
McDonagh's grisly cut was the result, he said, of his face slamming against the glass while his helmet visor came down against his lip.
Praseodymium is also a component of a special sort of glass, used to make visors to protect welders and glassmakers.
A pair of glasses dubbed a "privacy visor" has been developed to thwart hidden cameras using facial-recognition software.
Visors, glasses, or goggles fog, face masks become saturated and collapse toward the nose or mouth, suits and gloves tear, light fades, power outages occur, a patient becomes agitated, fatigue or heat stress intrudes.
When wearing headgear with a visor (with or without glasses): Raise the right hand sharply, fingers and thumb extended and joined, palm facing down, and place the tip of the right forefinger on the rim of the visor slightly to the right of the right eye on the command of execution, ARMS.
When wearing headgear without a visor (or uncovered) and wearing glasses: Execute the Hand Salute in the same manner as previously described, except touch the tip of the right forefinger to that point on the glasses where the temple piece of the frame meets the right edge of the right brow.
If you haven't, you'll notice this latest gizmo, "Google Glass," strikes a close resemblance to Jordi's visor in Star Trek's Next Generation, as you can see here.
This isn't just a virtual reality eye piece as some high-tech visors and glasses are, but a new way to connect without lifting a finger.
