* Eye structure: Fish eyes are adapted to the aquatic environment. They have a special membrane called the nictitating membrane that acts like a built-in "eyeglass" to protect the eye from water and debris. This membrane can be pulled across the eye surface like a windshield wiper.
* Tear production: Fish do produce a lubricating fluid similar to tears, but it's a bit different from what we have. Their tear-like fluid mainly serves to keep the eye moist and free of dirt.
* No blinking: Unlike humans, fish don't blink to lubricate their eyes. They rely on their nictitating membrane and the constant flow of water around them to keep their eyes clean and moist.
So, while water might come into contact with a fish's eye, it doesn't cause discomfort or irritation like it would for us.