Introduction to Refractive Errors
Your eye works much like a camera. As light enters into the eye it’s focused by the cornea and the lens onto the retina which is like the film inside your camera. When the image isn’t focused directly on the retina it appears blurry, and that’s why people use glasses or contact lenses to get that image into focus. Refractive errors can fall into three basic categories: nearsightedness, farsightedness, and astigmatism. In nearsightedness patients can see things up close but they have problems with their distance vision. In farsightedness people see things relatively well in the distance but have problems with their up close vision. And with astigmatism pretty much at all times images are blurry.