When light waves hit horizontal reflective surfaces like the surface of water, the light waves are transformed into polarized light. The vertical waves are absorbed while the horizontal waves bounce off the water’s surface.
These horizontal waves then reach the eye to produce blinding glare and block visibility into the water.
Only quality polarized sunglass lenses can remove the blinding glare of horizontal light. The removal of this light thereby enables you to see deep into the water. The naked eye or unpolarized sunglass lenses will not allow you to see into water.