Definition: “Second sight” refers to a temporary change in vision during early cataract development. Before vision deteriorates, vision, especially close-up reading vision, improves significantly. Some patients report very clear near vision without the use of reading glasses. Near vision refers to vision for objects 2 feet or closer to the viewer. These changes occur because the proteins and other compounds that make up the lens begin to change structure. This in turn changes the way light refracts through the lens, causing a temporary improvement in near vision.