An ophthalmological device according to one aspect of the present disclosure includes a support structure, an illumination light source, an observation optical system, and a controller. 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 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.
