An ophthalmologic apparatus includes an acquisition unit and a controller. The acquisition unit includes an optical scanner capable of deflecting light in a predetermined deflection angle range. The acquisition unit is configured to acquire data of a subject's eye by performing A-scan on the subject's eye using optical coherence tomography by measurement light deflected by the optical scanner. The controller is configured to cause the acquisition unit to perform A-scan based on a deflection operation state of the optical scanner.