Before tinting, lenses need to be properly fitted into the manufactured frame. Therefore, the lens need to be ground to fit the frame's size and shape. Also, some lens have to be ground according to the prescription in order to solve refractive errors in the customer's vision. Myopic vision is one example of an eye problem that would require a prescription for sunglasses. Other sunglasses prescriptions could be for bifocals, progressive bifocals and trifocals which would require a larger size lens to accommodate the lens progression.

The grinder that is used to grind the lenses to the specifications of the prescription is called an edger. There is a constant source of water running over the lens while it is being ground in order to reduce the heat caused by friction on the glass. The friction heat can cause glass to crack or break. Water also makes the grinding easier and smoother on the edge and prevents scratching of the surface from dry glass grit.

When the grinding is completed and the lenses are cleaned, tint is added to the lens by dipping the lens in a tint solution which is absorbed into the lens. The longer it is dipped, the darker the tint. The lenses are thoroughly rinsed and dried. They are then fitted into the sunglasses frame and the frame is secured tightly around the lens by tightening the screws on the frame. Sunglasses frames are mass-produced from products like plastic, nylon, carbon fibre and metal.

The process of making sunglasses has come a long way from when Roman Emperor Nero held polished light emerald glass gems up to his eyes and the Chinese attached ceramic weights to the ends of ribbons draped over the ears in order to keep on their cool sunglasses.

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