These look interesting but thee does not appear to be a liner of any sort. I would be concerned about the leather inside basically rubbing against the lens of my expensive glasses over time
seedeeveeAside from the lenses, a lot of "plastic" frames are vegetable acetate, which is a nice material but prone to instability over the long term. Skin oils, relative humidity, and other factors contribute to bubbling and that milky fading you sometimes see. So I wouldn’t want it rubbing up against another non-inert material.