If you spend a lot of time outside, without eye protection, you risk getting Pterygium. The reflective nature of water increases your risk. Pterygium is so common among water athletes that the household name is “Surfers' Eye”. The main symptom is a growth of pink, fleshy tissue on the clear tissue that lines your eyelids and covers your eyeball. To avoid surfers' eye, wear a good pair of sunglasses while paddling.
If you are looking for advice on preventing or treating rubbing or chafing, look here: Rubbing and Chafing