Shaykh Saalih Al-Fawzaan was asked:
May Allah bless you. If a woman has very weak eyesight, can she wear the niqaab and glasses whether they be eyeglasses or sunglasses?
“If she covers her face, she can wear colored eyeglasses. [Glasses] in which what is behind them of the face cannot be seen. There is no harm in that. There are glasses that conceal what is behind them [in terms of the face] and at the same time she can also see what is behind the glasses. They do not prevent her from seeing and they cover what is behind them in terms of her face. She wears them with the niqaab. Yes”
Faisal Ibn Abdul Qaadir Ibn Hassan