1) Cascades 2) River drops 3) Waterfalls 4) Waterfalls in the eyes 1) Falls 
in medicine, an opacity of the crystalline lens of the eye obstructing partially or totally its transmission of light NOTE - Cataracts can result from several causes, including irradiation.
Damage to the eye lens, which impairs vision. It is often caused by UV-B radiation, which is usually filtered out by the ozone layer.
A cloudy or opaque area in the lens of the eye. Excessive exposure to ultraviolet radiation (sunlight) is a cause of cataracts.