It was really random - they were dailies, and just one set one day became really painful after a few hours outside. They were in a box I had kept but not opened for many months, but sealed obviously.

At first I thought it was "just" a migraine (but incredibly painful) so I didn't go to the doctor or really notice that much until over a month later.

It's only really noticeable if I close my other eye and try to read stuff that would be right in the centre of the eye. But the worst part is looking at bright white screens e.g. Google Docs background etc. is really disorienting.

Rigid gas permeable lenses can loses their coatings, and allergies/sensitivities to the preservatives in most cleaning solutions can develop over time. Both caused me problems, luckily a year of wearing glasses allowed me to recover. Now I only use hydrogen peroxide based cleaning solutions without extra ingredients. Much better, except for global supply chain problems right now....