A surgical system used to determine if a vessel is within a region proximate to a working end of a surgical instrument includes at least one light emitter disposed at the working end of the surgical instrument, the at least one light emitter adapted to emit light of at least two different wavelengths. The system also includes at least one light sensor disposed at the working end of the surgical instrument opposite the at least one light emitter, the at least one light sensor adapted to detect light at the at least two different wavelengths. The system further includes a controller coupled to the at least one light sensor and adapted to determine a ratio of the light absorbed at the least two different wavelengths, and to indicate if an artifact within a region proximate to the working end of the surgical instrument is a vessel based on the ratio.