Hyperopia and convex lenses

Hyperopia, colloquially referred to as “farsightedness,” is a visual impairment that accounts for roughly 50% of the visual impairment of the US population. This condition involves the correct image to be focused past the retina, resulting in blurred vision for objects located close to the human eye. Convex lenses are often used to correct for this impairment, typically in the form of contact lenses or glasses. Further, refractive surgery involves the manual reshaping of the cornea to produce the correct, sharp image directly onto the retina of the human eye.

A research team is investigating the properties of a convex lens with a focal length of 20cm. The team uses an optical bench, which allows the lens, an object, and a screen to be fixed in place on the bench. A portion of the bench is seen in the diagram. The distance between adjacent lettered points on the bench is 10cm. The lens is fixed at point E.

Figure 1. The apparatus for the research team.