How to Select the Right Frame Size for Glasses

• The importance of eyeglass frame size is often overlooked
• The size of the frame is usually marked like 50□20-140 on the glasses. What does this mean? So, What frame size fits you? 
• Appropriate glasses should make the pupil basically in the center of the lens
• Simply: pupillary distance = glasses bridge + single lens width
• pupillary distance = distance between the center of right lens to the center of left lens
• The larger lens has a higher error tolerance rate, but the smaller lens has a very low error tolerance rate and must be basically in the center of the lens.