The phrase "a permanent eye" is correct and usable in written English.
It can be used in contexts where you want to describe something that has a constant or unchanging observation or perspective.
Example: "The surveillance system provides a permanent eye on the premises, ensuring security at all times."
Alternatives: "an unchanging gaze" or "a constant watch".
For making a permanent eye (closed circle) in a single rope, the eye splice, in which the free end is unlayed and interwoven at some point in the standing part of the rope, is employed, especially on sailing vessels.
For 40 years now, the Nasa/USGS satellites have maintained a permanent eye on Earth.
"You're bad!" she yelled at the man, whose frequent use of the vestibule as a toilet has given the area a permanent, eye-stinging stench.
John Coomer said he had suffered a detached retina and permanent eye damage when struck by a hot dog thrown by the Royals mascot, Sluggerrr.
Observers are advised not to stare directly at the sun without eclipse glasses, a properly filtered telescope or a strong welding visor – permanent eye damage could result.
After serving as deputy schools chancellor under Mayor Edward I. Koch, he ran the Office of Operations for Mayor David N. Dinkins as a more-or-less permanent eye over the shoulders of commissioners.
Sitting at the computer for hours at a time can result in permanent eye, back, and muscle pain, and/or temporary muscle pain.
"A laser incident in and of itself is not going to cause permanent eye damage to a pilot.
Attempting to look at the sun with the naked eye or an optical device, like a telescope or binoculars, can result in permanent eye damage.
Attempting to look at the eclipse with the naked eye, sunglasses or an optical device, like a telescope or binoculars, can result in permanent eye damage, so visit The Exploratorium's website for tips about how to safely view the astronomical phenomenon.
If you don't take precautions, permanent eye damage is a real consequence.
