lens /lenz/ (noun) a curved piece of glass or plastic that makes things look larger, smaller or clearer when you look through it Example: I have two pairs of glasses with different coloured lenses.
bifocals /ˌbaɪˈfəʊklz/ (noun) a pair of glasses with each lens made in two parts. The upper part is for looking at things at a distance, and the lower part is for looking at things that are close to you. Example: The doctor looked at me again over his bifocals as he wrote something in his book.
corrective lens /kəˈrɛktɪv lɛnz/ (noun) is a lens (i.e. a transmissive optical device) that is typically worn in front of the eye to improve daily vision Example: The doctor said I needed to wear corrective lens.
adjustable focus /əˈdʒʌstəbl ˈfəʊkəs/ (noun) are eyeglasses with an adjustable focal length. Example: Adjustable focus eyeglasses are eyeglasses with an adjustable focal length.
safety glasses /ˈseɪfti ɡlɑːsɪz/ (noun) special pieces of strong glass or plastic in a frame that fits tightly to a person's face to protect their eyes from dangerous chemicals or machines Example: Goggles or safety glasses are forms of protective eyewear.
sunglasses /ˈsʌnɡlæsɪz/ (noun) a pair of glasses with dark glass in them that you wear to protect your eyes from bright light from the sun Example: Should everyone have to wear sunglasses?
3D glasses /θriː diː ɡlɑːsɪz/ (noun) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. Example: We use 3D glasses to watch this movie.
bioptics /bʌɪˈɒptɪks/ (noun) head-mounted eyeglasses of extreme magnification Example: Bioptics are a combination two-lens optical system with a telescope attached to a pair of glasses.
contact lens /ˈkɑːntækt lenz/ (noun) a small round piece of thin plastic that you put on your eye to help you see better Example: All contact lens users must remove and clean their lenses as instructed.