I finally received a response from Oakley:
Thank you for contacting Oakley! I'm happy to answer your questions.
The differences between these lenses are the technologies that are applied to them.
The Oakley True Digital lenses are our standard lens technology.
The OTD Advance lenses are a more customized technology, which allows for additional measurements to be added to the lens to make sure your prescription is as accurate as possible. If this option is chosen, we will need your pupillary distance measurement. This can either be written on the prescription or supplied via call or email upon ordering.
The OTD Advance Plus lenses are an option for lenses that have a higher curvature. This includes both the above technology and the addition to a specialized groove to the edge of the glasses. This groove blocks the distortion that sometimes occur when higher prescription are applied to high curvature lenses.
Thank you for contacting Oakley! I'm happy to answer your questions.
The differences between these lenses are the technologies that are applied to them.
The Oakley True Digital lenses are our standard lens technology.
The OTD Advance lenses are a more customized technology, which allows for additional measurements to be added to the lens to make sure your prescription is as accurate as possible. If this option is chosen, we will need your pupillary distance measurement. This can either be written on the prescription or supplied via call or email upon ordering.
The OTD Advance Plus lenses are an option for lenses that have a higher curvature. This includes both the above technology and the addition to a specialized groove to the edge of the glasses. This groove blocks the distortion that sometimes occur when higher prescription are applied to high curvature lenses.