I think you can safely assume they are plastic lenses. Glass lenses are hardly ever used in glasses because they are heavy and they shatter easily. Ultra-high index glass lenses are normally used only for some extremely high prescriptions. If your lenses have an antireflective coating you will ruin it with Armour Etch.

Take your hand that your wear a ring on. Now go over to a glass window pain and tap the ring against the window. Listen to the sound it makes. Glass causes a sharp higher pitched click than plastic. Now go over to something made of plastic. It needs to be a pretty hard type plastic for comparison. Tap the ring against the plastic. Now tap the ring against your lenses. If you notice a sharp higher pitched clicking sound they are probably glass. If they sound more like a clunk than a click then they are probably plastic.

They are plastic, that's the only kind of lenses I've ever had in mine. I don't know of anyone that wears real glasses lenses in their frames.

I don't think glass is used any more for glasses they are plasticjust maybe they should call corrective lenses "plastics"