Changes in contrast sensitivity perception due to protector screens for welding tasks: conventional protective optical filter vs novel protective optical filter of selective absorbance

Abstract

AbstractPurpose To evaluate differences in contrast sensitivity perception in central visual field using protective optic filters for welding tasks. Two interposed filters are compared: a conventional protective optical filter and a new protective optical filter with selective absorption designed by University Complutense of Madrid (UCM).Methods 36 people of working‐age were included in a cross‐sectional prospective observational study. Contrast sensitivity threshold in central visual field was evaluated using FDT Perimeter, C‐20 procedure (Humphrey systems, USA). Three conditions were set: a) without optical filters; b) with an interposition of conventional protective optical filter for welding (shade 2.5) and c) with an interposition of a novel protective optical filter of selective absorbance that fully blocks the short wavelength light and minimally attenuates the remaining bands of the visible spectrum.Results Contrast sensitivity in all visual field areas evaluated diminished 91‐98% with the conventional protective optical filters. UCM optical filters provoked a low‐level decrease in contrast sensitivity (9‐19%). Mean contrast sensitivity thresholds were 29.5±5dB, 25.5±4dB, 1.8±2dB in conditions a, b and c respectivelyConclusion Conventional optical filters resulted in drastically diminished contrast sensitivity. UCM optical filter minimally diminish the visual function, allowing a suitable visibility and also maintaining an appropriate level of protection against phototoxic damage.