Discuss this Article. They dilated my daughter's eyes 18 hours ago, and they're still dilated. Anyone that says the eyes are back to normal in 6 hours does not know what they're talking about. The job of an eye doctor is not let their patients go blind. Retinal issues are the number one cause of blindness in north america, and most limiting factor of seeing the retina is the size of the pupil.
A truss bridge is a bridge composed of connected elements (typically straight) which may be stressed from tension, compression, or sometimes both in response to loads. Truss bridges are one of the oldest types of modern bridges. The basic types of truss bridges are shown below.
Truss. Thus, for the most part, all beams in a truss bridge are straight. Trusses are comprised of many small beams that together can support a large amount of weight and span great distances. In most cases the design, fabrication, and erection of trusses is relatively simple.