Parts of sunglasses & their functions

What are the parts of sunglasses? 

If you’ve ever shopped for shades, you know there are a wide variety of options. Have you ever thought about the various parts of sunglasses like the lenses, frame front and temples, and how they fit together to create your perfect pair? Read on to learn the parts of sunglasses, their names and their functions.  

Lenses

One of the most important reasons for wearing sunglasses is to protect your eyes from damage that can occur from exposure to the sun’s ultraviolet (UV) rays. In the U.S., retailers selling sunglasses are required by law to state how much UV protection sunglasses provide. 

When you’re looking for sunglasses, check to make sure there is a sticker on the lens or a label that says they have 100% protection from UVA-UVB rays. The sticker might indicate that the glasses are rated UV 400. This means the lenses block almost 100% of damaging UV rays. For optimal eye safety, 75% to 90% of visible light should be blocked by the sunglass lenses.

READ MORE: UV and sunglasses: How to protect your eyes

You have options when it comes to choosing sunglass lenses, including:

• Polarization – Polarized lenses reduce glare and improve visibility, making them ideal for outdoor activities like fishing and skiing. It’s not a good idea to wear polarized lenses while driving at night or when there is ice on the road. In these situations, you want more light and need to see glare caused by ice so you can drive safely.

• Tint – Lens tint comes in many colors, and some colors can help you see better in different conditions. For example, if you play outdoor sports, lenses that are tinted green, amber or gray improve contrast and can be a good choice. It’s important to remember that just because they are tinted doesn’t mean they provide extra sun protection. The same is true for very dark lenses.

• Mirror coating – This coating is added to sunglass lenses to reduce the amount of light that reaches your eyes. Like tinted lenses, mirrored lenses don’t necessarily protect your eyes from UV rays unless labeled as having UV protection.

• Photochromic lenses – These lenses darken when exposed to UV light and go back to clear when indoors. The lenses also adjust in different lighting conditions. 

• Gradient lenses – Gradient lenses are darker at the top and gradually become lighter toward the bottom. They lend a softer, more subtle look to the overall aesthetic of the sunglasses.

Sunglass lenses generally are made with these materials:

• Polycarbonate – This is a durable, impact-resistant plastic lens that has UV protection built in.    

• High-index plastic – These lenses are made of plastic material that is both thin and lightweight. 

• Glass – Glass lenses tend to be scratch-resistant and offer a high optical quality. However, they’re not always the best choice for sunglasses. They can be uncomfortable to wear for a long time because they are heavier than plastic lenses. They also are not impact resistant and could prove to be a dangerous choice if being used in a contact sport or in situations where something could hit you in the face, as they could shatter.

Keep in mind there are unlimited options when it comes to sunglasses, and your local optician can help you make the right choice. Certain tints have been shown to perform better than others during certain sports or activities. For instance, if you are an avid golfer or biker, there are specific lenses that can enhance your experience.  

If you wear prescription eyeglasses, you can (in most cases) get sunglasses with prescription lenses. If you need help, talk to your eye care professional. 

Frame 

The frame is what surrounds the lenses and gives the sunglasses their size and shape. The frame you choose, such as wayfarer, cat eye, round or oversized, is a way you can express your individual style. 

Sunglass frames are most often made of plastic, metal or a combination of these materials. 

Metal frames

Metal frames are generally lighter and more flexible than plastic. Here are some reasons you may want a metal frame: 

• Strength – Metal frames are strong and durable and often hold up, even if you’re hard on your sunglasses. 

• Lightweight – There are several metals that are used in frames, such as titanium and stainless steel. Metal frames are typically lightweight and many are also flexible.

• Resistant to corrosion – Beryllium is a corrosion-resistant metal. This is a beneficial feature if you go to the beach often or participate in saltwater activities like boating or water skiing.

• Hypoallergenic – If you’re allergic to certain types of metal, like nickel, you can choose frames made from flexon or titanium, which are hypoallergenic.   

Plastic frames

If you’re looking for a wide variety of colors and patterns, plastic frames are the way to go. Here are some more benefits of plastic frames:

• Budget friendly – In many cases, plastic frames are more affordable than metal. However, this may not be true if you choose designer sunglasses.

• Hypoallergenic – Plastic frames generally don’t contain metal, which could make them an ideal choice if you have a metal allergy.

• Lightweight – Many plastic frames are lightweight so you can wear them comfortably for several hours at a time.    

Wood frames

If you’re looking for something different, you may want to try sunglasses with a wood frame. These frames are eco-friendly and biodegradable; however, they are almost impossible to adjust. Make sure the frame fits you from the first time you try it on to avoid potential regrets after your purchase. 

Frame front plate

The frame front plate is the part of the frame that holds the lenses in place. It gives a pair of sunglasses their shape. You can choose sunglasses with a full rim or that are semi-rimless, which means the rims don’t completely surround the lenses. The bridge is another component of the frame front. It holds most of the frame’s weight and contributes to the overall comfort of your glasses. 

Nose pads

Nose pads are mostly found on sunglasses with wire frames. They are small cushions often made from silicone or soft materials that help your sunglasses sit comfortably on your nose. Very seldom do plastic frames have adjustable nose pads.

Nose pad arms

These are tiny pieces that connect the nose pad to the frame. You can adjust the nose pad arms to help your sunglasses stay on your face.   

Temple

The temples, or arms, are the sidepieces that extend from the frames to reach and fit over your ears. They keep your sunglasses from falling off of your face. Temples come in different lengths to accommodate a variety of facial features and head sizes.  

Temple tips

Temple tips are the parts of the temple that rest behind your ears. They are often made with acetate or metal covered in silicone or rubber to prevent slippage and to help ensure your sunglasses are comfortable for you to wear.

Hinges

The hinges allow you to open and close the temples without breaking your glasses. One part of the hinge is attached to the frame and the other is attached to the temple.  

Screws

The screws are what hold the parts of the hinge together so the temples stay connected to the frame. 

READ MORE: Parts of glasses & their functions

What’s the difference between sunglasses and eyeglasses?

Sunglasses and eyeglasses look the same and have the same parts. The main difference is the purpose. Eyeglasses help you see better by correcting vision problems such as nearsightedness, farsightedness or astigmatism. Sunglasses can have prescription lenses for vision correction but are primarily worn to protect your eyes from harmful UV rays.

Many eyeglass wearers are unaware that they can get sunglasses with their prescription in them and struggle with the bright sunlight because of this. If you are someone who requires prescription eyewear, be sure and ask your eye care professional about prescription sunglasses as well. 

Now that you know more about sunglasses, you’ll be able to choose a pair that protects your eyes, feels comfortable and looks great.

SEE RELATED: National Sunglasses Day

Page published on Tuesday, January 30, 2024

Page updated on Tuesday, February 6, 2024

Medically reviewed on Sunday, January 21, 2024