[Cut-off filter : Physical and physiological basics].

Light filters with wavelength-dependent transmission and in particular cut-off or step filters (steep dependence of transmission on wavelength) have a broad optical application and are relevant in ophthalmology. This article describes some physical and physiological principles of cut-off filters, discusses the physiological aspects of applications, specifically the not always relevant necessity of blue-reducing filters and the lack of efficacy of color filters with color vision deficiencies.