Astigmatism
Yes, an orange is roughly the shape of a sphere, though it is not a perfect sphere. It is more accurately described as a spheroid, as it may have slight irregularities and a slightly flattened shape at the poles. However, its general roundness resembles that of a sphere.
A flat piece of glass. Also, any lens where the shape of the convex part matches the shape of the concave part. An example would be a flat piece of glass bent over a sphere.
irregularities
of Irregularity
The shape you're describing is commonly referred to as a "cylindrical lens" or more generally, a "lens shape." In geometric terms, it can also be considered a "superellipse" or "oval rectangle" depending on the specific proportions of the semicircles to the rectangle. However, in everyday language, it is often simply called a "rectangle with semicircles."
a shape of a lens is curved outwards and concave one are curved in wards
A magnifying lens is typically convex in shape.
A converging lens is also known as a magnifying lens. The shape of the lens is a double convex shape.
The testes should be free from lumps, pain, irregularities and swelling.
The role of a lens is to converge and or diverge light depending on the shape of the lens.
A lenticular shape: the shape of a lens.
NO
Rectangle
A concave circle
The lens changes its shape by becoming more convex (thicker in the middle) when focusing on near objects. This shape change is controlled by ciliary muscles in the eye that pull on the lens to make it rounder, allowing for proper focusing on close-up objects.
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.
The lens is normally transparent, elliptical in shape, and somewhat elastic.