Believe it or not, most high-end, designer sunglasses aren’t actually higher quality than those $40 “knock off” shades you might find in a department store, since the vast majority of sunglasses are actually made by the same company.

Luxottica, a high-end, Italian manufacturer, makes sunglasses for such brands as Versace, Ray Ban, Polo Ralph Lauren, Oakley, Revo, and more. Luxottica also owns several of the major sunglass retailers in the United States, including Sunglass Hut, LensCrafters, and Pearle Vision. The same company that makes the sunglasses is usually the one selling them, as it turns out

Obviously, the price reflects both the material and labor that went into manufacturing the sunglasses, but the cost also reflects marketing, brand values, and how much people are willing to pay. After deducting brand licensing royalties, overhead, and advertising and sales costs, Luxottica will make a gross profit of 52 cents for every dollar of sales.

The real question here is whether or not Luxottica’s higher end sunglasses can protect consumers’ eyes better than their lower end models.

According to the American Optometric Association (AOA), the longer someone exposes their eyes to solar radiation, the bigger risk there is of developing ocular conditions, like macular degeneration or cataracts. Though it’s unclear how much exposure it takes to develop such medical conditions, the AOA recommends wearing sunglasses that can block out at least 99% of of both UV-A and UV-B rays, and screen between 75% to 90% of visible light.

Essentially, protection is all about the lenses–not the frames. According Dr. Jay Duker, the chair of ophthalmology at Tufts Medical Center, “Three hundred dollar sunglasses don’t do anything better than $100 sunglasses, except maybe look better and have a brand name associated with them.”

But what if the lenses are scratched or broken? Do consumers really need to buy exorbitantly priced replacement lenses, or can they get affordable, aftermarket replacements?

“The Sunglass Fix estimates that you can’t get replacement lenses from the manufacturer in about 95% of sunglasses sold,” explains Craig Anderson, CEO of The Sunglass Fix. “And even if you do, it usually costs you in the neighborhood of 60 to 80% of the original purchase price. The Sunglass Fix was started primarily because of this frustration, and the disposable nature of the sunglass industry. We’ve found that we can manufacture and produce lenses that not only match the original quality of lenses sold in an $800 pair of sunglasses, but that we can often exceed them in optical clarity and durability.”

As summer quickly approaches, forgoing those $400 aviators for a $40 pair of sunglasses appears to be the much savvier choice. “A significant chunk of what you pay for isn’t the quality of the lenses,” says Dr. Reza Dana, director of the cornea and refractive surgery service at Massachusetts Eye and Ear Infirmary. “It’s the brand.”