An optometry apparatus comprising: a pair of right and left lens units disposed in an optical path of a target light flux projected onto an examinee's eye, configured for changing an optical characteristic of the target lifght flux; a drive means configured for driving the lens units ; a control means configured for controlling driving of the drive means ; an acquisition means configured for acquiring a targeted visual acuity value at the time of fogging and to additionally aquire a measured visual acuity value of the examinee's eye; and an operation means , wherein the acquisition means is configured to acquire the targeted visual acuity value on the basis of an operation signal output from the operation means in accordance with an operation by the examiner, wherein the control means is configured to determine an amount of fog for fogging the examinee's eye on the basis of the targeted visual acuity value acquired by the acquisition means and the measured visual acuity value of the examinee's eye acquired by the acquisition means , wherein the control means is configured to determine the amount of fog on the basis of a power corresponding to the targeted visual acuity value and a correction value corresponding to the visual acuity value of the examinee, wherein the correction value is a power obtained by conversion of the degree of blurring corresponding to the visual acuity value of the examinee, wherein the correction value is obtained by converting a displacement between the image forming position of the examination target that enters the examinee's eye that has been corrected and the retinal position of the examinee's eye into a lens power. a pair of right and left lens units disposed in an optical path of a target light flux projected onto an examinee's eye, configured for changing an optical characteristic of the target lifght flux; a drive means configured for driving the lens units ; a control means configured for controlling driving of the drive means ; an acquisition means configured for acquiring a targeted visual acuity value at the time of fogging and to additionally aquire a measured visual acuity value of the examinee's eye; and an operation means , wherein the acquisition means is configured to acquire the targeted visual acuity value on the basis of an operation signal output from the operation means in accordance with an operation by the examiner, wherein the control means is configured to determine an amount of fog for fogging the examinee's eye on the basis of the targeted visual acuity value acquired by the acquisition means and the measured visual acuity value of the examinee's eye acquired by the acquisition means , wherein the control means is configured to determine the amount of fog on the basis of a power corresponding to the targeted visual acuity value and a correction value corresponding to the visual acuity value of the examinee, wherein the correction value is a power obtained by conversion of the degree of blurring corresponding to the visual acuity value of the examinee, wherein the correction value is obtained by converting a displacement between the image forming position of the examination target that enters the examinee's eye that has been corrected and the retinal position of the examinee's eye into a lens power. <EOS>