You may well be wondering if the traditional sight test, i.e. subjective refraction, is necessary at all, if it leads to inaccuracies. The answer is yes. The optician must be able to record your personal reaction to the various lenses he or she inserts in front of your eyes. Just as importantly, subjective refraction also tests how your eyes interact and how they will see with your new spectacles.
However, there are ophthalmic instruments such as the ZEISS i.Profiler®plus which can be used to perform objective refraction beforehand. It uses wavefront technology to analyze the vision profile of each eye on the basis of 1,500 measuring points and generates a "map" of the eyes’ retinas. No active collaboration of the patient is required. All he or she needs to do is look into the i.Profiler®plus for a short time. This is a preparatory measurement, the results of which are then refined by the optician in the subsequent subjective refraction procedure.
And that is not all: as the i.Profile®plus measures visual performance with a contracted pupil (in bright light) and a dilated pupil (in poor light or at night), it is possible to determine whether the patient's night vision is poorer than his or her daytime vision (And suddenly you see more). The optician can use this information to incorporate the appropriate optimisations in the lenses. A major benefit of this procedure is that the time required for the eye sight may be reduced.