Computer program comprising instructions that, upon execution of the program by a computer, cause the latter to carry out a method comprising the following steps: a) presenting at least one symbol at at least one first distance in front of at least one eye (112, 112') of a user for stimulating the accommodation of the at least one eye (112, 112') by means of a device configured for presentation purposes; b) registering at least one eye movement of the at least one eye (112, 112') by means of an eye movement measuring device configured to register at least one eye movement of the at least one eye (112, 112'); and c) ascertaining a refraction of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance by means of at least the eye movement measuring device or a refraction measuring device configured to register the refraction of the at least one eye (112, 112'); and d) jointly determining the accommodation and the vergence of the at least one eye (112, 112') by - ascertaining a change in the refraction of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance in relation to the accommodation of the at least one eye (112, 112') at at least one second distance; - ascertaining the vergence of the at least one eye (112, 112') from the at least one eye movement of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance; characterized by e) ascertaining a change of myopia of the at least one eye (112, 112') of the user from a ratio of the vergence of the at least one eye (112, 112') to the change in the accommodation from the change in the refraction of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance in relation to the accommodation of the at least one eye (112, 112') at the at least second distance. a) presenting at least one symbol at at least one first distance in front of at least one eye (112, 112') of a user for stimulating the accommodation of the at least one eye (112, 112') by means of a device configured for presentation purposes; b) registering at least one eye movement of the at least one eye (112, 112') by means of an eye movement measuring device configured to register at least one eye movement of the at least one eye (112, 112'); and c) ascertaining a refraction of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance by means of at least the eye movement measuring device or a refraction measuring device configured to register the refraction of the at least one eye (112, 112'); and d) jointly determining the accommodation and the vergence of the at least one eye (112, 112') by - ascertaining a change in the refraction of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance in relation to the accommodation of the at least one eye (112, 112') at at least one second distance; - ascertaining the vergence of the at least one eye (112, 112') from the at least one eye movement of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance; characterized by - ascertaining a change in the refraction of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance in relation to the accommodation of the at least one eye (112, 112') at at least one second distance; - ascertaining the vergence of the at least one eye (112, 112') from the at least one eye movement of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance; characterized by e) ascertaining a change of myopia of the at least one eye (112, 112') of the user from a ratio of the vergence of the at least one eye (112, 112') to the change in the accommodation from the change in the refraction of the at least one eye (112, 112') with the accommodation of the at least one eye (112, 112') at the at least one first distance in relation to the accommodation of the at least one eye (112, 112') at the at least second distance.