Field-of-View Evaluation of the Preplanned Product Improvement Visual Correctionof the M40 Protective Mask

摘要

The purpose of this study was to evaluate the field-of-view (FOV) of a proposedpreplanned product improvement (p3I) visual correction for the M40 protective mask. Two prototype mounting brackets for the p3I visual correction were used in the investigation: one with an eye well loop and the other with a Velcro strip. It was found that the proposed p3I visual correction provides the same FOV as its predecessor despite its larger size. The failure of the proposed p3I visual correction to provide a larger FOV was determined to be excessive vertex (eye to visual correction) distance. In addition, it was found that there was no difference between the FOVs obtained with either of the two mounting brackets. The study identified a problem of excessive vertex distance when the P 3 I visual correction is worn inside M40 mask sizes small and large.