A stereographic display apparatus and a vehicle headlight can include an optical modulator including a position sensor and a voltage supply. The position sensor can be configured to detect an inclined angle, and the voltage supply can be configured to apply a voltage to the optical modulator in accordance with the inclined angle output from the position sensor. The optical modulator can refract light at a refraction angle in accordance with the voltage output from the voltage supply. Therefore, when the optical modulator is incorporated into a stereographic display apparatus, the stereographic display apparatus can provide comfortable stereographic displays to viewers, even if it inclines due to hand movement and the like. A vehicle headlight incorporating the optical modulator can also form light distributions in a useful direction for drivers with a simple structure, even when it moves in various directions with reference to a road due to road conditions.