That is happened on both sides was good news and bad news. It ruled out scratches on the retina and similar causes. My next suspicion was a allergic reaction to one of the preservatives in the solution that the lenses came in (I always used the contacts directly out of the original packaging, without rinsing them first). So I got some contact lens solution, and soaked a pair for a while before putting them in - problem solved. Or so I thought.
Next time we wanted to go sailing, the pain was back - impossible to keep the lenses in. While waiting for my eyes to get back to normal, I did some internet research. I had not quite believed that the cause was an allergic reaction, since the pain was instantaneous - allergies typically take a little while. I know: I aced my allergy test, with 36 positive reactions against the 40 allergens tested!
I did find a few references about the boric acid and sodium borate that is used in most contact lens solutions being a problem. The borate is used as a buffer, to keep the pH constant. But a second reason that it is used is that is slightly toxic - it is anti-microbial. You can use concentrated borate solutions to kill ants - they think it's sugar water, and die a bit later. A scientific study even showed that borate-based contact lens packaging solutions can kill eye cells (human corneal epithelial cells, if you want to know the specifics).
At the local drugstore, I found that almost all contact lens solutions contain borate. Even the "Sensitive eyes" and "Saline" solutions use borate as the buffer. But fortunately, one of the many solutions was phosphate-based and borate-free. In my initial tests, soaking the lenses in this solution fixed the problem. Let's hope this holds up!
Below are a few pictures that Mike Murphy took during a recent session: