Originally posted by victormeldrew Nonsense. A saline solution is perfectly harmless for your eyes but I would strongly suggest you don't spray any onto your camera. Anyway, none of these things are designed to be sprayed onto your eyes, they (at most) are to be sprayed onto glasses, or goggles, then wiped off, then placed near the eye, so eyes are irrelevant.
None of the things they are designed to be sprayed on are either electronic, metal, rubber, or coated in highly expensive optical coatings that the manufacturer says in no uncertain terms should only be cleaned with a soft dry cloth.
Originally posted by photoptimist I'd second that warning. Any detergent or surfactant is likely to degrade the water-repellant properties of the seals and o-rings. Moreover, on exposure to oxygen the film of anti-fogging chemical will oxidize into an organic acid which may damage the AR coatings.
P.S. Saline solution is 100% safe for human eyes and 100% deadly for electronics.
Originally posted by victormeldrew I personally would be careful as a lot of anti-fogs are just detergent solutions, which are not likely to be good for lens coatings or lubricants.
Originally posted by jack002 "Safe for your eyes" -- why did you use those words about what people put on glasses? I don't put glasses on my eyes, they don't touch my eyes?
Glasses lenses and camera lenses are vastly different in how they should be treated.
Glasses do not have delecate coatings or seals around them that hold out water and dirt. Very different.
I got a lot of push back on my suggestion "anti-fog agent" "why would you say safe for eyes"!
Well lenses for glasses in some cases are coated and yes it is possible to damage the coatings on them if you use "isopropyl alcohol"
https://sciencing.com/remove-antireflective-coating-eyeglasses-7631108.html
As for safe for the eyes some solutions release fumes that could cause your eyes to water and sting when pressed against the view finder, although the following link is about safety and swim goggles I would be careful what I used on my viewfinder or binoculars.
Corneal injury by anti-misting agent in swim goggles: a case report. - PubMed - NCBI
I hope I have been a little more thorough in my response to Allens inquiry about lenses and viewfinder fogging up on entry to greenhouses.
What I had also stated in an earlier post that I have "uv filters" on all my lenses, so perhaps a solution is to coat the UV filter with "anti-fog" agent
rather than put it directly on the lens if you are worried about damage to the lens coatings, although I would think this would be addressed by those that manufacture the agent for use on photographic lenses.
What is an "anti-fog agent?"
Anti-fog - Wikipedia