Deadly sunglasses

Sunglasses without protection from the harmful UVA and UVB rays can be harmful to the eyes. Cheap sunglasses often do not block out the ultraviolet light that can cause damage to the retina. Cheap shades reduce the amount of visible light entering your eye, allowing you look without squinting. Furthermore, the pupil dilates to compensate for the decrease in ambient light. This can be very harmful for your eyes because you have opened up the window for UV light to enter the eye. In fact, being outside without sunglasses, causing your pupil to constrict and forcing you to squint is better for your eye health than wearing cheap sunglasses.
Be careful where you buy sunglasses, be sure that they block UVA and UVB. Also be wary of claims that they block UV light as there are not FDA regulations concerning UV blocking claims. Some sunglasses may have a sticker on them touting UV blockage but it is only partial UV protection. Cheap can be OK  but be careful, you only have one set of eyes and damage from the sun is permanent.