Cylindrical lenses are used to correct astigmatism in the eye, and, in rangefinders, to produce astigmatism, stretching a point of light into a line. Some styles of cylindrical lenses have antireflective coatings to increase the transmission of light through the lens.

Spherical lenses, also known as singlets, are transparent optical components consisting of one or more pieces of optical glass with surfaces curved to converge or diverge the transmitted rays from an object, thus forming a real or virtual image of that object.  

There are seven main spherical lens forms, or shapes, that determine the imaging characteristics of the lens.  They are plano-convex, plano-concave, convex-convex, concave-concave, meniscus, aspheric, and ball.  Plano-convex lenses have a positive focal length, which makes them ideal for collecting and focusing light for many imaging applications.  Plano-concave lenses have a negative focal length and are used for image reduction or to spread light.  Convex-convex lenses have a positive focal length and are useful for 1:1 imaging and in multi-element systems. Also known as biconvex or equiconvex.  Concave-concave lenses have negative focal length, and are used for image reduction and to spread light. Also known as biconcave or equiconcave.  Meniscus lenses can increase the numerical aperture of a positive lens assembly, without an undue increase in the aberrations.  Aspheric lenses compensate for spherical aberration and are used primarily for their light gathering ability.  Ball lenses are used to provide short focal lengths for use with collimated light.  They are often used in fiber coupling applications.  While the above seven are the most common types, there are other, rare styles of spherical lenses available.

Common materials of construction for optical windows include BK7 glass, crown glass, calcium fluoride, germanium, photonics DIAMOND, sapphire, thermoset ADC, UV grade fused silica, and zinc selenide.  Some windows are coated to increase transmission of light at the lens-air interface. Coatings for optical windows include none, antireflective, and conductive.  Surface quality ratings for optical windows include 10-5 scratch / dig, 20-10 scratch / dig, 40-20 scratch / dig, 60-40 scratch / dig, and 80-50 scratch / dig.  A dig is a defect on a polished optical surface that is nearly equal in terms of its length and width. A scratch is a defect on a polished optical surface whose length is many times its width.  10 / 5 indicates the average diameter of the digs to be .05 mm and the average length of a scratch is .10 mm.  20 / 10 indicates the average diameter of the digs to be .10 mm and the average length of a scratch is .20 mm.  40 / 20 indicates the average diameter of the digs to be .20 mm and the average length of a scratch is .40 mm.  60 / 40 indicates the average diameter of the digs to be .40 mm and the average length of a scratch is .60 mm.  80 / 50 indicates the average diameter of the digs to be .50 mm and the average length of a scratch is .80 mm.  Choices for surface flatness for optical windows include /2, /4, /5, /8, /10, and /20.

Selecting optical prisms requires an analysis of surface quality and surface flatness specifications. Scratches are defects whose lengths are many times greater than their widths. Digs are defects that are nearly equal in length and width. Optical prisms with a 10-5 scratch/dig surface quality have scratches with an average length of .10 mm and digs with an average diameter of .05 mm. Optical prisms with a 20-10 surface quality have an average scratch length of .20 mm and an average dig diameter of .10 mm. Products with 40-20, 60-40, and 80-50 scratch/dig quality measurements are also available. Surface flatness, another important specification, is expressed in terms of whereλ = 633 nm. Typically, the largest variation in surface height is no larger than λ/ 2, λ/ 4, λ/ 5, λ/ 8, λ/ 10, orλ/20.

Achromats consist of two or more lenses, which must be fixed in relation to one another by either mounting or cement. They are a very common type of viewer lens.  Achromats consist of two or three lens elements (referred to as doublets and triplets, respectively), which have been corrected for chromatic aberration with respect to two selected wavelengths. These devices are often referred to as achromatic lenses.  Achromats are designed to specifically function within the infrared, visible, or ultra-violet wavelength ranges, optimized for three wavelengths, 486.1, 587.6 and 656.3nm.  Achromats are not symmetric devices.  They must be installed with the correct font-to-back orientation (thicker element usually faces the eyes).  If installed incorrectly, with the lens orientation installed backwards the result will be extensive distortion and aberration.

Achromats are generally manufactured from crown glass and flint glass; although other materials such as fused silica and BK7 positive glass may be used.  The crown and flint glass elements are housed in a metal cell and separated by a spacer.  The air gap acts as a third lens element and provides a greater degree of correction than found in a cemented lens.  In this way it is possible to balance the aberrations over a fairly wide range of wavelengths so that the lenses perform well as broadband imaging devices. The crown glass forms a positive lens; the flint glass, a negative perspective, with a reduction in longitudinal color foci of about 0.05 percent.  Such lenses are usually designed to focus blue and red light to the same position, with all other colors focusing at either slightly longer or slightly shorter focal lengths. The discordant 0.05 percent is the longitudinal distance between where red and blue focus, resulting in a green focal point.