6. (foll by: to) related (to) or dependent (on). 7. (when: postpositive, often foll by to) having a subsidiary or minor relationship (with). 8. (General Physics) (esp of a beam of light or particles) arriving at or striking a surface: incident electrons.
Answers (1) hill. Personally, if you use salt water properly, it won't cause any damages to your sunglasses. But if you rinse your sunglasses in salt water for a long time, it may cause some damages to the lens coating of your sunglasses. Anyway, you needn't rinse your sunglasses in salt water.
In addition to the features for sports glasses, water sunglasses can have increased buoyancy to stop them from sinking should they come off, and they can have a vent or other method to eliminate fogging.