Free Shipping
Price Match
Easy Returns
Licensed Opticians
The Arnette Cortex 4291 sunglasses bring bold square styling and eco-conscious construction to your everyday rotation. Built from bio-acetate—a sustainable material made from up to 70% renewable resources—these frames deliver the durability and comfort Arnette is known for, with a lighter environmental footprint. The 57mm lens width and 18mm bridge offer a medium fit that works for most face shapes, while the full-rim acetate construction keeps things lightweight and secure during active wear. Prescription lenses can be added to make these your daily drivers.
Sustainable Materials That Perform
Arnette has committed to sustainability since 2019, and the Cortex 4291 is part of that effort. The bio-acetate frames are derived from cellulose (cotton or wood fiber) and topped with bio-based plasticizers instead of fossil-fuel alternatives. The lenses are made from castor oil, a renewable resource. This means the frames use plant-based materials instead of petroleum-based plastics, reducing reliance on fossil fuels while maintaining the strength and flexibility you need. Even the packaging is thoughtful—the pouch is 78% recycled polyamide, and the box is fully recyclable.
Multiple Colors Including Polarized Options
Choose from several colors to match your style and functional needs. Polarized options help cut glare for water and driving. All lenses provide 100% UV protection. The square shape suits angular and oval faces, and the 140mm temples ensure a stable fit that won't slip during movement. These are built for the street, the beach, or anywhere in between.
Product Details
Product DetailsModel
0AN4291Shape
Gender
Material
Bridge Type
Rim Type
Age Group
Color Details
Color DetailsColor Code
275625Color Description
Transparent VioletLens Color
Light Azure Mirror Teal
Frame Color
TortoiseColor Code
277083Color Description
Dark AvanaLens Color
Polar Brown
Color Code
27716GColor Description
Transparent YellowLens Color
Grey Mirror Silver 80
Frame Color
BlackColor Code
275887Color Description
Matte BlackLens Color
Dark Grey
Frame Color
BlackColor Code
27539AColor Description
BlackLens Color
Dark Green Polar
Color Code
28416GColor Description
Dark GreyLens Color
Light Grey Mirror Black
Color Code
275922Color Description
Matte Dark BlueLens Color
Dark Grey Mirror Water Polarized
Color Code
285887Color Description
Transparent Light GreyLens Color
Dark Grey
Frame Color
BlackColor Code
290073Color Description
BlackLens Color
Dark Brown
Size Details
Size DetailsSize
5718-140
Size
5718-140
Size
5718-140
Size
5718-140
Size
5718-140
Bridge Width
18.00Temple Length
140.00Size
5718-140
Bridge Width
18.00Temple Length
140.00Size
5718-140
Bridge Width
18.00Temple Length
140.00Size
5718-140
Bridge Width
18.00Temple Length
140.00Size
5718-140
California Proposition 65 Proposition 65 is a California regulation that requires special warnings to be presented to customers if a product contains certain quantities of chemicals or toxicants known to the State of California to cause cancer, birth defects, or other reproductive harm. The following warning applies to the products linking to this page:
WARNING: Reproductive Harm – https://www.p65warnings.ca.gov/Free Shipping within the contiguous US only (excluding Hawaii and Alaska) on all Orders over $100.
At DesignerOptics.com we are committed to the highest quality of service.
We ship products to all 50 US states as well as to many other countries around the world. We take all the measures to ship our items in a timely manner, directly to your door, almost anywhere in the world.
In stock products usually ship within two business days, but may take up to five business days*. When an order ships you will receive a confirmation email with the tracking information. You can also track your order by logging into your account.
We provide FREE SHIPPING on all orders over $100 We also offer overnight and second day delivery shipping options. Please note that when using next day or second day delivery it still takes 48 to 72 Business hours for the order to be processed.
The Designer Optics Low Price Guarantee is simple:
Designeroptics.com matches the price of all retail competitors and major online retailers.
How it works:
Place the frames in your cart
Before placing your order in add the following the comments box, Add the URL (web address) of the page where you found the lower-priced item,
Your credit card will not be charged until we have confirmed with you by phone or by email that your item qualifies for our Price-Match Guarantee.
Please Follow those easy steps for returns
1- Please fill out this form Return Authorization Form to get an RMA # you will receive a RMA # with instruction on how to return them within 48 to 72 Business hours from the time you submitted the form. Wait for our confirmation e-mail before shipping back the return
2- Send the product back to us following the instructions indicated in our e-mail and to the address we will provide you.
3- Make sure to confirm with us via e-mail the shipping date, the shipping service you used and the tracking number whenever you have
4- Include details of the return and how you would like for us to go about it (refund, store credit, exchange, etc). Designer Optics is not responsible for items damaged along the way.
Please allow us 3 to 5 business days from when items are received for us to process the refund. The amount to be refunded will not include shipping charges. if the order consists of 3 or more frames we will charge a 20% Restocking fee. otherwise only the shipping will be deducted.
Some exclusions may apply. Please note prescription lenses are final sale. We also do not accept returns on beauty products due to health and safety concerns. For more information please go to Returns
At Designer Optics, our skilled and experienced lab opticians play a crucial role in ensuring the quality and accuracy of your eyewear. With over 30 combined years of experience and full licensure, they review each prescription carefully and are equipped to answer any questions you may have.
Our state-of-the-art lab is equipped with the latest technology and equipment, including advanced edging and cutting technology, to produce lenses that are precise and accurate. Whether you need full frame or rimless lenses, our team is dedicated to providing the best possible results.
For personalized support, simply send an email to Support@designeroptics.com to request a call back from one of our friendly opticians.
Frequently Asked Questions
Are the Arnette Cortex 4291 sunglasses prescription-ready?
Yes, the Arnette Cortex 4291 sunglasses are fully prescription-ready. The acetate frames can accommodate single-vision, bifocal, or progressive prescription lenses. The 57mm lens width and full-rim construction provide ample space for most prescription types, making them a practical choice for daily wear with your Rx.
What size are the Arnette Cortex 4291 sunglasses?
The Arnette Cortex 4291 measures 57mm lens width, 18mm bridge width, and 140mm temple length. This is considered a medium fit suitable for most adult face sizes. The 57mm lens width is the standard measurement that determines whether sunglasses are small, medium, or large.
Are Arnette Cortex 4291 sunglasses made from sustainable materials?
Yes, the Cortex 4291 is part of Arnette's sustainable collection. The frames are made from bio-acetate containing up to 70% renewable raw materials derived from cotton or wood cellulose. The lenses are made from castor oil, and the packaging uses 78% recycled polyamide. This construction reduces reliance on fossil-based plastics while maintaining durability.
Do the Arnette Cortex 4291 sunglasses have UV protection?
Yes, all Arnette Cortex 4291 sunglasses include lenses with 100% UV protection to shield your eyes from harmful UVA and UVB rays. Several colorways also offer polarized lenses, which reduce glare and improve visual clarity on water, snow, and other reflective surfaces.
What face shapes work best with the Arnette Cortex 4291?
The Arnette Cortex 4291 features a square frame shape that works best for oval and round face shapes, as the angular lines provide contrast and definition. The 57mm lens width is a medium size that suits most face widths. The full-rim design and 18mm bridge ensure a secure, comfortable fit for daily wear.
Which Arnette Cortex 4291 colorways have polarized lenses?
Three colorways of the Arnette Cortex 4291 feature polarized lenses: 277083 (Havana/Polar Brown), 27539A (Black/Dark Green Polar), and 275922 (Blue/Dark Grey Mirror Water Polarized). Polarized lenses reduce glare from reflective surfaces and improve contrast, making them ideal for driving, water sports, and bright outdoor conditions.
Compare With Similar Frames
How the Arnette Cortex 4291 Sunglasses stacks up against the closest alternatives we carry.
- Similar square acetate construction
- Comparable price range
- Prescription-ready like the Cortex
Read the full comparison
Arnette Cortex 4291 vs. Arnette Adios Baby! 4272
If you're choosing between two Arnette square frames, the Cortex 4291 and Adios Baby! 4272 share the same sustainable bio-acetate DNA and prescription-ready construction. The Cortex offers more versatility with 9 colorways including three polarized options, making it the better choice if you want variety or need glare reduction for water sports and driving. Both sit in the same affordable price range and deliver Arnette's signature streetwear-inspired style. The Cortex's wider color selection and polarized availability give it the edge for most buyers.
Arnette Cortex 4291 vs. Carrera 5039
The Carrera 5039 offers a similar square acetate frame at a comparable price ($74.35-$75.92), but the brand positioning differs significantly. Arnette leans into surf, skate, and street culture with sustainable bio-acetate materials, while Carrera brings motorsport heritage and Italian design. If eco-conscious construction matters to you, the Cortex 4291's 70% renewable materials and castor oil lenses are a clear advantage. If you prefer Carrera's racing-inspired aesthetic and don't prioritize sustainability, the 5039 is a solid alternative. Both are prescription-ready and offer full-rim durability.
Why Choose the Arnette Cortex 4291?
The Cortex 4291 stands out for its combination of sustainable materials, prescription versatility, and affordable pricing. With 9 colorways—including polarized options—you get more choices than most competitors at this price point. The bio-acetate construction reduces environmental impact without sacrificing durability or comfort. For buyers who want square frames that work for both style and function, with the option to add prescription lenses, the Cortex 4291 delivers exceptional value.
At a Glance
Arnette Adios Baby! 4272 Sunglasses
Pros:
- Similar sustainable bio-acetate construction
- Comparable price point ($71.59 vs $58.21-$154.75)
- Same prescription-ready capability
- Square frame shape with similar styling DNA
Cons:
- May have different sizing (need to check specific measurements)
- Fewer colorway options compared to Cortex's 9 variants
- Less availability of polarized options
Carrera 5039 Sunglasses
Pros:
- Similar square acetate construction
- Comparable price range
- Prescription-ready like the Cortex
- Carrera's motorsport heritage appeals to different aesthetic
Cons:
- May not use bio-acetate sustainable materials
- Different brand positioning (motorsport vs. streetwear)
- Potentially different fit and sizing