-In addition to the cameras, projectors and magnifiers mentioned above, convex lenses are also used in telescopes. A telescope usually consists of an objective lens and an eyepiece. The objective lens is a convex lens with a long focal length, which is used to collect light rays from a distant object and form an inverted, reduced image; the eyepiece is a convex lens with a short focal length, which is used to magnify the image formed by the objective lens again, thus allowing us to see objects in the distance clearly.

–Convex lenses in ophthalmology are used to correct hyperopia. Farsightedness is a result of the small the anterior and posterior dimensions of the eyeball or the tiny convexity of the lens that causes light radiations to diverge from the retina. With convex lenses, the light rays are able to converge earlier, so that the image is precisely onto the retina thereby correcting the vision.

-In a solar cooker convex lenses are employed to condense light rays an area and increase the temperature of that point in order to be used to heat water and cook food.

As we mentioned before Concave lenses are mostly used to treat myopia. The cause of myopia lies in the lengthy both the posterior and anterior diameters of the eyeball, or the huge convexity of the lens, causing light beams to converge on the retina. Concave lens spectacles are they diverge the light beams tiny bit before they enter the eye, allowing the image to hit the retina, allowing myopic patients to see distant objects with clarity.

-In mirrors for doors (cat’s eyes) the concave lens is often fitted. When you view through the cat’s eyes from outside the door, to within the house the inside gets larger due to the angle of view that is increased as the concave optical lens causes light to diverge, making it possible for more of the inside of the home to be visible. If you look out from inside the home due to the design of the door mirror only a small portion of the house can be observed that can be used to ensure the security of the home.