Triangle Envelope Case
Single vision lenses have the same prescription throughout their entire surface. They can correct either distance or near vision.
Reading glasses provide near vision correction in strengths ranging from +0.75 to +3.50. They are available with or without prescription.
Non-prescription lenses are clear or tinted lenses, made available to those who do not require vision correction.
Multifocal lenses (progressive, degressive or anti-fatigue) contain two or more prescriptions, at once providing correction for various distances.