An ophthalmologic apparatus that is configured to measure, by light interference, a dimension of an eye to be examined, the ophthalmologic apparatus comprising: a light source; an incidence member that is configured to cause light from the light source to be incident on a plurality of different positions in the eye to be examined; an acquisition unit that is configured to acquire a two-dimensional tomographic image of an interior of the eye to be examined on the basis of a plurality of interference signals acquired as a result of the incidence member causing the incidence of light on the plurality of different positions; a first calculation unit that is configured to calculate an ophthalmologic measurement value of a measuring portion inside the eye to be examined by determining positions of portions of the eye to be examined on the basis of the plurality of interference signals, the portions of the eye to be examined including a front surface of a cornea, a rear surface of the cornea, a front surface of a crystalline lens, a rear surface of the crystalline lens, and a surface of a retina; a display unit that is configured to display the acquired two-dimensional tomographic image; and a correction unit that is configured to correct the ophthalmologic measurement value of the measuring portion from the two-dimensional tomographic image displayed by the display unit; wherein the display unit is further configured to display the positions of the portions of the eye to be examined that are determined by the first calculation unit with the acquired two-dimensional tomographic image, the apparatus being characterized in that the correction unit comprises: a first designation unit that is configured to be operated by an examiner to designate a new position for at least one of the positions of the portions of the eye to be examined with respect to the two-dimensional tomographic image displayed by the display unit; and a second calculation unit that is configured to recalculate the ophthalmologic measurement value on the basis of the new position designated by the first designation unit. a light source; an incidence member that is configured to cause light from the light source to be incident on a plurality of different positions in the eye to be examined; an acquisition unit that is configured to acquire a two-dimensional tomographic image of an interior of the eye to be examined on the basis of a plurality of interference signals acquired as a result of the incidence member causing the incidence of light on the plurality of different positions; a first calculation unit that is configured to calculate an ophthalmologic measurement value of a measuring portion inside the eye to be examined by determining positions of portions of the eye to be examined on the basis of the plurality of interference signals, the portions of the eye to be examined including a front surface of a cornea, a rear surface of the cornea, a front surface of a crystalline lens, a rear surface of the crystalline lens, and a surface of a retina; a display unit that is configured to display the acquired two-dimensional tomographic image; and a correction unit that is configured to correct the ophthalmologic measurement value of the measuring portion from the two-dimensional tomographic image displayed by the display unit; wherein the display unit is further configured to display the positions of the portions of the eye to be examined that are determined by the first calculation unit with the acquired two-dimensional tomographic image, the apparatus being characterized in that the correction unit comprises: a first designation unit that is configured to be operated by an examiner to designate a new position for at least one of the positions of the portions of the eye to be examined with respect to the two-dimensional tomographic image displayed by the display unit; and a second calculation unit that is configured to recalculate the ophthalmologic measurement value on the basis of the new position designated by the first designation unit. a first designation unit that is configured to be operated by an examiner to designate a new position for at least one of the positions of the portions of the eye to be examined with respect to the two-dimensional tomographic image displayed by the display unit; and a second calculation unit that is configured to recalculate the ophthalmologic measurement value on the basis of the new position designated by the first designation unit.