ABSTRACT
As any other optical instrument with image-forming lenses, the eye has optical aberrations that limit its optical performance. When an eye is larger than normal but the refractive components do not change their optical properties, the image of an object at infinity is defocused. This is what happens in myopia. In hypermetropia, the mechanism is exactly the opposite. An ophthalmic lens corrects this defect, shifting the real image formed by the optics of the eye to the new position. An ophthalmic lens is a thin meniscus lens placed in front of the eye to correct its refractive defects. This lens is mounted in a frame in such a way that the distance from the vertex of the concave surface to the cornea of the eye is 14 mm. The image formed by the ophthalmic lens should also be at a constant distance for any object in the object surface.
