Presbyopes are lenses made of convex lenses used to correct presbyopia and have a magnifying effect when looking at close objects. Myopia lenses are lenses made of concave lenses used to correct myopia and have a magnifying effect when looking at near objects. Presbyopia is a physiological weakening of the adjusting function due to ageing, resulting in a lack of clarity when looking at near objects. Myopia is the result of increased refractive power of the eye, or growth of the eye’s axis, resulting in unclear viewing of long-distance items. In addition, presbyopia is expressed as a positive number in the refractive error and myopia is expressed as a negative number.