Temperature limits of Contact Lenses

[sandeepgoodbole]

What are the upper and lower limits of Ambiant Temperature in which the Contact Lenses can be safely worn, without damaging the eyes?

[drk]

I doubt there is any lower end...tears don't readily freeze. They're salty.

I guess since heat is associated with dryness, there may be an issue with evaporation, but not "melting".

[chip anderson]

All types of contact lenses can endure a far greater temperature range than the patient can. Get the patient cold or hot enough to kill him and the lens still has a long way to go.

And no a contact lens never melted on a welder's eye.


Chip

[sandeepgoodbole]

What will happen at subzero centigrade temp, at 8 thousand feet altitude ? Frost bite of Cornea by Contact Lens is possibility ? Water containt is a parameter for freezing ? What is the Salt % of tears. Is it NaCl ?

[chip anderson]

More likely the contact lens would provide some insulation. But as you know gogles are to be used at such temps and altitude. Contact lenses stay at the temperature of the eyeball. If it gets cold enough to freeze your body parts, the lenses will freeze with them. The lenses will not cause the cornea or lid to freeze but if you get frozen solid the lenses will freeze with you. Also remember that the lenses and tears are basicly salt water so they have to get a bit colder to freeze than water. Now spares kept in your gear, they may need to either be insulated, or warmed for use.

No wonder I can never catch you on line, you're off climbing them mountians again.

The good news is you will be in better shape than people that have refractive surgery at this altitude. Some take months for the cornea's and vision to recover from the low pressure.

Chip

[Yeap]

The contact lens will take the temperature of the eye (body which are 37.6 Celsius) so no matter how cold or hot the environment the lens will not melt or froze. if you say about the frost bite the cornea that maybe lens drying up due to the low humidity of the environment, but as Chip mention, always have a goggle for that purpose that able to protect the lens temperature..

[MarcE]

And no a contact lens never melted on a welder's eye.


Chip

Of course they can't melt to the eye, Chip. That's just silly.

But they do slide back behind the eye and get stuck on the brain.

Seems to happen mostly early Sunday morning, according to the phone calls made to the doctor.

[HarryChiling]

What is the Salt % of tears. Is it NaCl ?

9 Parts per Million, the tears contain both Sodium and Potassium so sodium chloride (NaCl) is a good guess as well as potasium chloride (KCl).