Clip-on sunglasses are not actually sunglasses in the real sense, but they are an arrangement of a pair of lenses designed to fit on another pair of sunglasses. One can attach clip-ons to any pair of glasses and convert them into something totally different.

Clip-ons are comprised of two lenses attachable by a spring mechanism. Each lens is fitted with rod and a tube towards the nasal side in such a manner that the rod of one lens enters the tube of the other and is held together by the spring mechanism. This helps in increasing or decreasing the linear distance between the two lenses. Over the nasal rim they have attachments by which they can be fit on the existing pair of sunglasses.

One trendy modification is that a pair of clip-ons that can be attached to a hat, so that the wearer suffers no discomfiture of side rims. Magnetic clip-on sunglasses are available that attach to the rim of the existing glasses. They are convenient because they are easy to slip on and off. Clip-ons are also available in the flip-clip variety, which enables the wearer to flip the clip-on sunglasses when desired.

Clip-ons are not just fashion accessories; they can have several purposes. Clip-on lenses may be polarized, UV resistant, prescriptive, or with whatever other ophthalmic improvisation that the wearer seek. A person can change ordinary glasses into a pair of polarized sunglasses or prescriptive sunglasses.

Clip-ons need to be light since they are going to be attached on another pair of glasses. They can be made of glass, polycarbonate, or CR-39. Glass is scratch-resistant but it is heavy and brittle. Polycarbonate is ideally preferred, but CR-39 provides the best visual quality. The variety of tints and shapes in clip-ons is seemingly endless and each brand has its own versions of clip-ons on the market.

Wearers of prescription glasses can convert their mundane looking lenses into something fashionable by attaching a glitzy pair of clip-ons. The clip-ons do not affect the quality of their vision and are ideal for people who wish to mask the fact that they are wearing prescription glasses.

The absence of a frame makes clip-ons cheaper than other sunglasses. The prices vary from brand to brand and design to design. It is imperative to opt for a good quality genuine clip-on or it will adversely affect the vision of the person.