Because they alter the focus of the lens in the patients eye, to correct their vision.
Your are mixing properties. Converging lens is always thicker in the centre and thinner at the edges. The other cathegory is the geometry of shape of the surfaces of the lens. Convex means that the shape is similar to the outer surbace of a sphere, concave means that the shape is similar to the iner surface of a sphere (or: convex = lower side of a spoon as we use it for sampling a soup; concave: upper (inner) shape of the spoon). A double convex lens is always a converging lens. A plano-concave lens is always a diverging (not converging) lens. A convexo-concave lens is the most usual shape of a lense used in spectacles. It can be either converging or diverging, depending on the radii of the surfaces.
Spectacles typically use lenses made of optical glass or plastic, which can be either convex or concave depending on the wearer's vision needs. These lenses are then customized with prescriptions to correct different vision problems such as nearsightedness, farsightedness, and astigmatism.
A concave mirror converges light rays to a focal point, while a concave lens diverges light rays away from a focal point. Concave mirrors are used for focusing light, such as in telescopes and makeup mirrors, while concave lenses are used for dispersing light, such as in correcting nearsightedness.
Lens are widely used. The most common example of the usage of lens is the spectacles. The spectacles contain either convex or concave lenses. In some cases it is plane. Convex Lens are widely used in Magnifying glasses, Microscope and Telescopes. Convex lens are used in torch lights. It helps in concentrating the light rays emitted from the bulb to a point, hence increasing the intensity of light at that point.
Image formed by a concave lens or a diverging lens is virtual,upright and smaller than the object.It is used by short sighted people.
They are convex, or rounded outward. The title is given from where you view through them - from convex to concave. The image is in focus from this direction
Your are mixing properties. Converging lens is always thicker in the centre and thinner at the edges. The other cathegory is the geometry of shape of the surfaces of the lens. Convex means that the shape is similar to the outer surbace of a sphere, concave means that the shape is similar to the iner surface of a sphere (or: convex = lower side of a spoon as we use it for sampling a soup; concave: upper (inner) shape of the spoon). A double convex lens is always a converging lens. A plano-concave lens is always a diverging (not converging) lens. A convexo-concave lens is the most usual shape of a lense used in spectacles. It can be either converging or diverging, depending on the radii of the surfaces.
a lens that caves in like this )( as opposed to convex which puffs out like this (). a concave lens. it is used to bend and focus light
Spectacles typically use lenses made of optical glass or plastic, which can be either convex or concave depending on the wearer's vision needs. These lenses are then customized with prescriptions to correct different vision problems such as nearsightedness, farsightedness, and astigmatism.
A Concave lens is used to correct short- sightedness.
)( is a concave lens() is a convex lens
A concave lens is a lens that is thinner at the center and thicker at the edges. It is used to correct myopia (nearsightedness) by diverging light rays before they enter the eye, thus helping to focus the image on the retina. Concave lenses are often used in glasses or contact lenses for people with nearsightedness.
CONCAVE LENS : lens that atleast possess one end inwards is called as concave lens. CONVEX LENS : lens that atleast possess one end outwards like the exterior of the sphere is called convex lens. According to the medical values convex lens are used for long sight vision problem and concave lens for short sight vision problems.
A convexo-concave lens is a lens that has one side convex (outward bulging) and the other side concave (inward curving). This type of lens can be used to correct myopia (nearsightedness) by diverging light rays entering the eye.
A concave mirror converges light rays to a focal point, while a concave lens diverges light rays away from a focal point. Concave mirrors are used for focusing light, such as in telescopes and makeup mirrors, while concave lenses are used for dispersing light, such as in correcting nearsightedness.
convex.
The ocular lens used for nearsightedness is known as a diverging lens. It is also known as a concave lens.