Companies that sell Oakley "style" products without the express authorization of Oakley are risking an infringement lawsuit. Oakley and other designer-based companies often are very aggressive in policing and protecting their intellectual property (which makes sense since much of their profit and livelihood stems from intellectual property). So, you are right to be concerned about possible infringement issues related to Oakley's trademarks and patents. That being said, replacement lenses may be considered permissible repair under patent law. This doctrine, however, may be more applicable where the patent is for the entire sunglass frame, and less so for a patent directed towards the lens itself. You should consult with an intellectual property attorney about researching Oakley's trademarks and patents to determine your risks for infringement for your specific situation, and how to proceed. Good luck.
This answer is for informational purposes only. It is not intended as specific legal advice regarding your question. The answer could be different if all of the facts were known. This answer does not establish an attorney-client relationship.
If you are using Oakley trademark not within the fair use exception then it would be an infringement but simply saying that it is compatible with Oakleys is not infringement.
If your design incorporates a design that is patented that is obvious improvement then it is infringement but if it is an improvement that is not obvious then it does not infringe. If you're trying to replicate what China does, don't. China doesn't enforce treaties regarding intellectual property but insists the US does for them. It is not fair but that is the reality.
This is just my opinion and not a comprehensive answer. You assume the risk because this answer may not apply to your situation depending on the facts.
You will have to conduct a clearance for each lens you want to sell. A clearance is simply a search of existing patents; if a patent does cover the lens, hopefully you will find it and either (1) license the patent from Oakley (not likely) or (2) avoid problems by not selling that lens.
I would be surprised if lens themselves are protected by utility or design patents, but I could be wrong. The Patent Office website (uspto.gov) has a very useful search tool for searching patents. Good luck!
I have represented clients against Oakley on patent matters. Historically, Oakley is very aggressive in enforcing their patents and trademarks through litigation. They have many patents on both their sunglasses as a whole (for example, dealing with reducing distortion of images for wraparound glasses) and for their lenses specifically (for example, on the color-mirrored coatings).
Before you proceed, you need to hire a IP attorney to review exactly what you are considering and to analyze any patents or trademarks that may be relevant.
The information contained in this answer is intended to provide general information only and not legal advice. You should consult with an attorney licensed to practice in your jurisdiction before relying upon any of the information presented here. Sending e-mail to or viewing or downloading information to me or my website does not create an attorney-client relationship.