Browline glasses are a kind of glasses frame in which the "bold" part of the glasses holds the lens, just like the browlines frame the eyes. They were very popular in the 1950s and 1960s, especially in the United States. The glasses were first produced by Shuron Co., Ltd. under the "Ronsir" brand in 1947 and were quickly imitated by other manufacturers. This design became the most common style of glasses in the 1950s and early 1960s and was later surpassed by solid plastic styles. In the 1980s, with the rise of retro style and hipster subculture, brown sunglasses made a comeback as sunglasses and then became popular again in the 2010s. Chinese Premier Li Peng died from 1989 to 2019 and wore diagonal glasses for 30 years.

Browline glasses are the upper part of the frame that is thicker than the lower half, used to simulate browline or draw attention to the wearer's natural browline.

The most common method of construction is that the upper part of the frame ("browline" or "hat") and temples are made of plastic, while the rest of the frame (bridge and eyeliner, or "chassis") is made of metal. The chassis is inserted into the browline and secured in place by a series of screws. For some time in the 1960s, there were many models of browlines made of aluminum; with the revival of this style at the beginning of the 21st century, browline made entirely of a metal part of the browline became popular.

Monobrowlines are a variant of browlines in which the bridge is contiguous with the caps, creating a solid, unbroken line across the top of the frame. The style dates back to the Shuron Stag, a browline prototype, which enjoyed some brief popularity before being replaced by the Ronsir as Shuron's flagship frame. The original stag had no metal chassis: the lenses were mounted directly to the brow caps via two sets of screws. Although the style was never popular in the United States, it became particularly fashionable in Europe and England in the 1960s as part of Amor's Spotlite line. The modern monobrowline originated in the 1980s, as part of an effort by Bausch and Lomb to diversify their Ray-Ban sunglass collection with the Wayfarer Max, a fusion of the then-popular Wayfarer and Clubmaster sunglass models.[1][2] The style proved unpopular and was quickly phased out. The monobrowline design was resurrected by a variety of manufacturers in the 2010s (chiefly Oakley) after browlines returned to popularity. Unlike its tenure in the 1980s, monobrow lines proved to be a popular variant among eyeglass wearers in the 2010s

In general, browline specs are great for users with narrow foreheads by helping to make them look wider and more balanced. With the many variations to the modern browline, it's not too hard to match this frame with any face shape, although there are things to consider with each one.

1. Oblong face
It's advantageous to wear browline frame glasses if you have an oblong-shaped face, helping to make it more square and wider. The oblong face is characterized as elongated and wearing these specs balances your facial proportions better.

With the browline's thick upper and thin wireframe, you will be able to highlight your jawline strength and cheekbone depth, which are unremarkable sans the glasses. Oblong faces are typically large, and this type of frame allows you to add more structure to your otherwise soft features.

2. Diamond face
Prominent cheekbones and an angular jawline are the distinct characteristics of the diamond-shaped face. What a browline frame does to this face shape is it adds extra bulk to even out the relatively narrow forehead. You can also soften your chiseled cheekbones and jaw if you opt for rounded browline glasses.

However, it's important to note that oversized browline forms can easily draw the diamond face shape, so it's better to opt for the regular-sized styles.

3. Square face
Browline glasses look stunning on square-shaped faces because it helps to mute the strong facial features and add a reflective, intellectual look to this imposing shape. It tames the chiseled jaw and cheekbones to give you a scholarly yet highly charismatic appearance.

If you want attention-grabbing frames, you can try dark-colored browlines and unique patterns that add more personality to your eyewear.

4. Oval face
The oval-shaped face is often regarded as the most ideal and it's a no-brainer that browline frame glasses will fit this type quite nicely. The bold upper rim helps the oval face's upper features to stand out, while the thin bottom frame enhances the soft lower facial structure.

With this shape, it's best to avoid oversized browlines as it can make the otherwise proportionally balanced face to become rounder and overly softened.