Eyeglass rating with respect to protection against UV hazard

摘要

An index value is calculated for rating an eyeglass with respect to protection against UV hazard. The index value is based on an integrated UV transmission value through the eyeglass and an integrated UV reflection value related to a back face of the eyeglass. Thus, the index value takes into account actual wearing conditions where UV eye exposure is due either to transmission through the eyeglass or reflection on the eyeglass back face. Respective index values obtained for a set of eyeglasses allow easy sorting of the eyeglasses with respect to UV protection efficiency.

主权项

1. A method of rating an eyeglass with respect to protection provided by the eyeglass against UV hazard, whereby an index value is calculated for quantifying a reduction in a total UV amount impinging onto an eye for a wearer of the eyeglass with respect to UV exposure without eyeglass, the method comprising:
obtaining a measurement of UV intensity, the measurement being generated by a photometer for light reflecting from a face of the eyeglass; providing a value of UV reflection on a back face of the eyeglass, the UV reflection being obtained by integrating spectral reflection values relating to the back face of the eyeglass; applying UV reflection of the eyeglass to a formula with a non-zero positive factor for the UV reflection; and calculating the index value from a non-zero base number divided by a result obtained in the applying step, the index value being based in part on measurements obtained from the obtaining a measurement step.