The decentration of the spectacle lens generates an additional sphero-cylindrical effect. The aim of this study is to examine its effect on the correction of the patient´s primary refractive error. In practice, we find minor or greater problems that are reflected in the intolerance of some types of spectacle lenses. More serious problems are in this case for aspheric spectacle lenses. In the practical part of this thesis we compare the sphero-cylindrical effect on the patient´s visual performance. We will perform binocular refraction measurements on the near, medium and long distance. We will use polarizing and anaglyph filters.

Results

The main object of this study was the effect of visual aberrations on the visual performance with spherical and aspheric spectacle lenses, which was evaluated by subjective measurements with individual respondents. They were allowed to wear both types of lenses and suddenly they could choose the ideal type to their glasses. Depending on the measured results, this study provides important information about the necessary need of a maximum 14-day adaptation for aspheric spectacle lenses to improve the patient's visual performance. Regarding measured visual acuity, both types of lenses allowed (for central and peripheral view) to achieve VA 1.0 after 14 days adaptation. Therefore, for the aspheric spectacle lenses, the average value of VA during the first measurement (without adaptation) was always worse compared to the spherical lenses. From the results of subjectively measured astigmatism of oblique rays for a viewing angle 30° it can be concluded that VA was probably not impaired by the residual refractive error, but due to greater distortion of the image with aspheric lenses. From the results of the measured image distortion after a 14-day adaptation, the deformation was significantly better (lower) with the aspheric lenses. It means that the aspheric lenses allowed a sharper vision to the periphery of lens. However, the question of "sharpness of vision" is a very individual parameter, and it is important to know that not everyone will prefer a sharper vision with aspheric spectacle lenses, which this study has confirmed. Despite the perfect shape of aspheric lenses, 71% of respondents chose to their glasses the basic type of spherical lenses. This study showed that the optometrist must take into account the earlier correction of the patient, the personal preference of the patient for his/her future correction, but also the type of personality of the individual candidates is very important for the right choice.

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