Heat dehydrates you, which increases your level of impairment. Operating a personal watercraft requires a person to pay close attention to many different things and make quick adjustments. Alcohol impairs the rate at which your brain can process information. A drunken watercraft operator cannot react to an unexpected situation as a sober operator would. Alcohol can also affect your vision by interfering with the ciliary muscles, which adjust the shape of the lens of your eye by contracting or relaxing to focus on objects at different distances.
Alcohol can also affect the muscles that rotate the eyeball.
These muscles normally work together so that both eyes are pointed in the proper direction to focus on an object. Under the influence of alcohol, the eyes may not work in tandem. This affects depth perception and, in more pronounced instances, may cause double vision. Drinking also reduces your peripheral vision. A drinker s vision becomes blurry and unfocused.