There are several advantages to using tempered glass and it should be the only glass used in safety applications and applications that require a lot of temperature changes (such as freezing and heating). Tempered glass is 4-5 times stronger than regular glass.
A visual migraine is a temporary visual distortion that often begins with a small sparkling, shimmering area that slowly expands outward. The growing spot often has jagged, zig-zag edges. The visual symptoms typically last approximately 20-30 minutes and then completely resolve.
Other visual aura symptoms. 1  Seeing spots, stars, halos, circles, lines, other shapes or colors. 2  Blurry vision. 3  Loss of vision.  Cloudy 1  vision. Other vision changes.  Seeing three-dimensional 1  effects. Seeing dark  areas.