[Measurement of contrast vision: mesopic or photopic vision? : Comparison of different methods for measuring contrast sensitivity within the framework of driving licence regulations].

BACKGROUND

Since 2011 the regulations for occupational driving licences make the examination of contrast vision sensitivity obligatory; however, apart from mesopic procedures no uniform regulations are available for methods and minimum requirements.

OBJECTIVE

By comparing different mesopic and photopic contrast sensitivity tests this study analyzed whether these could be equivalently used and lead to the same results.

MATERIAL AND

METHODS

Contrast vision sensitivity was determined in 150 subjects with emmetropia using five different methods, i.e. the mesopic test device Mesotest II as the reference method, Rodatest 302 and Optovist as photopic test devices and two photopic test charts (Vistech chart and Mars charts). The results of passing the tests were compared and Cohens κ was determined to quantify the conformity between the tests.

RESULTS

Poor agreement was found between Mesotest II and Optovist as well as between Mesotest II and the Vistech chart. There was no agreement between Rodatest 302 or Mars charts and Mesotest II; nevertheless, the contrast vision sensitivity measured with Optovist, Rodatest 302 and the Vistech chart showed good correlation (0.46 ≤ r ≤ 0.69).

CONCLUSION

Apart from a few limitations, the reference method Mesotest II as well as Optovist and the Vistech chart are suitable for testing contrast vision sensitivity, whereas Rodatest 302 and Mars charts cannot be recommended based on the current criteria for minimum requirements. The minimum requirements must be urgently adapted and strict regulations for measurement must be formulated. In addition, due to the poor agreement between the methods an amendment of the driving licence regulations should be considered, which requires examination of both mesopic and photopic contrast vision or alternatively mesopic contrast vision alone.