Development and evaluation of a photo-rhinometer for clinical use

We developed a photo-rhinometer (PRM) which is a modification of the Glatzel nasal mirror, and which can promptly evaluate nasal patency under natural respiration without any facial apparatus. We also investigated the clinical applications of the PRM. In PRM operation, moisture deposits resulting from expiratory nasal flow onto a glass plate are visualized for the right and left nostrils separately with an image analyzing computer at a television scan rate of 1/30 of a second. These visualized moisture deposits are averaged over the initial 1 second and differentiated for the initial 90 milliseconds to obtain an average moisture deposit area (AMDA) and the velocity of the moisture deposit (VMD), respectively. The resulting PRM chart, a graphic presentation of the moisture deposit area versus time was expected to be useful for the visual evaluation of nasal patency. PRM measurements were performed on 100 adult volunteers who were selected without knowing whether they had any nasal symptoms or disorders. Results showed that statistical distributions of both AMDA and VMD were equivalent to the normal distribution. A significant correlation was observed between nasal conductance as determined by a rhinomanometer and AMDA as determined by the PRM, and also between the nasal conductance and the VMD, which is r = 0.66 and r = 0.78 respectively. In addition to the 100 cases, five cases of chronic sinusitis and ten cases of acute sinusitis, which had been conservatively treated, were investigated by using the PRM. In some of these cases where improvements in the nasal conditions and reduction of subjective nasal obstruction were recognized, increases in the AMDA and VMD showed a good correlation with improvements in the nasal disorder.