A "Chasmis girl" simply refers to a girl or woman who wears eyeglasses (glasses).
The term "Chasmis" (or "Chashmish") originates from the word "Chashma," which translates to "glasses" or "spectacles" in languages like Hindi and Urdu. Therefore, the term is a straightforward descriptor based on the individual's wearing of glasses. It's essentially a descriptive label, nothing more.