Frame sizes and Scientist research

Scientists through extensive research calculated average head sizes

In the field of Anthropometry scientist with the aid of your anatomical structures developed the average head face sizes. I took this information and devised face sizes based off my interpretation of this information, and like magic it has worked well for my customers over the years. Moving on, optical engineers have designed eyeglass frames for the length of one’s face, based on scientific research.

As follows:

Menton (chin) Measured from top of head (midline) to bottom of the chin. Vertical distance measured in centimeters.

Small Medium Large
Men 21.2 cm 23.2 cm 25.5 cm
Women 19.8 cm 21.8 cm 23.8 cm

The structure of eyeglass frames is based on the golden ratio (1:1.618) of the human face, primarily the length of the face that usually dictates the temple length (arm piece that holds the sunglasses on your head) of the frame

Menton-Crinion (midpoint hairline) Measured from Midpoint hairline to mid bottom of chin. Vertical length of the face measured in centimeters.

Short Average Long
Men 16.6 cm 19.1 cm 21.6 cm
Temple sizes 120 – 130 mm 130 – 140 mm 140 – 150 mm
Women 15.5 cm 17.7 cm 19.9 cm
Temple sizes 115 – 125 mm 125 – 135 mm 135 – 145 mm

Because the width of the face is 3-dimensional forehead (temple to temple), cheek bones (cheek to cheek), and jaw bones (jaw to jaw) there must be an added factor the bridge size to determine width. In addition, the width of the of the frame must cover the widest part of the face I.e., the forehead, the jaw or most commonly the cheek bones. Although I can determine the narrowness or broadness of one’s face, with this information alone I am unable to determine your face shape. In my section Determining your face shape I will explain in detail how to measure the three horizontal face widths. Because of the 3 variances of your facial widths, I can generalize eye sizes absence bridge sizes.

Bitragion breadth (width) Measured from right to left tragion (tragion is the notch at the front of the ear). Horizontal width of the face measured in centimeters.

Narrow Normal Broad (wide)
Men 13.1 cm 14.5 cm 16.0 cm
Eye size range 51 – 64 mm 59 – 69 mm 65 – 75 mm
Women 12.5 cm 13.8 cm 15.0 cm
Eye size range 49 – 58 mm 55 – 65 mm 59 – 69 mm

These eye sizes are only a guide and does not reflect the actual eye size, because the width of your face must be added into the equation, for example a narrow head woman can wear an eye size 51mm with a bridge size 22mm or eye size 55mm with a bridge size 15mm. But most of these eye sizes will fall within the Menton-Crinion guidelines. As a final factor in choosing the scale (size) of your sunglasses is the shape of your face. For example, a person with a base-down triangle face would need to wear size larger to balance off the narrow forehead of the face.

https://en.wikipedia.org/wiki/Human_head#nerve_supply

Frame weight Indicated for Frame Sizes Frame eye/bridge
HV heavy over 40 grams large broad features LG large over 63/18
med medium 20 – 40 grams normal features med medium 53/19 – 63/17
sm small  under 20 grams small delicate, child-like sm small under 53/19