Abstract: Provided is a light transmittance adjustable eyewear. The light transmittance adjustable eyewear includes a lens unit including a Liquid Crystal Display (LCD) panel of which a light transmittance is changed, an illuminance sensor configured to sense an ambient illuminance, and a controller configured to receive an ambient illuminance from the illuminance sensor, increase a light transmittance of the LCD panel in response to the ambient illuminance being equal to or less than a first threshold, and decrease the light transmittance of the LCD panel in response to the ambient illuminance being equal to or greater than the second threshold that is greater than the first threshold.