system
Given the following post, respond as if you're commenting on Reddit:
human
If our tears are salty, why does salt water sting our eyes?

I've always been curious as to why my eyes burn underwater in the ocean but my tears always taste salty.
gpt
Great question! Let's consider any differences in those two types of saltwater. Now aside from microorganisms and other nutrients and minerals present in seawater the main difference is that the oceans are saltier than our tears. That is not to say our tears are not salty- medical fluids such as IV drips or contact solution have a small amount of salt in them to match the fact that our bodies have small amounts of salts dissolved (Na, K, Ca, Cl mostly). Pure water would be bad to put into a person actually, and small amounts of salts prevent over or dehydration. tl;dr In short, more salts in seawater than tears- so it stings. Tears don't sting because they have as much salt as your body already is working with in them.