An ophthalmological device (1) according to one aspect of the present disclosure includes a support structure (7), an illumination light source (301, 302), an observation optical system (300), and a controller (700). The support structure is configured to support a subject's face. The illumination light source is configured to illuminate a subject's eye. The observation optical system includes an imaging element (306) configured to receive light reflecting off the subject's eye. The controller is configured to acquire, from the imaging element, a first image captured when the illumination light source is on and a second image captured when the illumination light source is off and determine whether the subject's face is placed on the support structure based on a difference between the first image and the second image.
