1. An ophthalmologic apparatus comprising: an acquiring unit that acquires a plurality of images of an eye to be inspected; a determination unit that determines, using a processor, an image among the plurality of acquired images that is less affected by movement, during the image acquiring, of the eye to be inspected; a selection unit that selects an image which is a part of the image determined by the determination unit; and a detecting unit that detects movement of the eye to be inspected using the selected image.