The Feasibility of Utilizing Smartphone Flashlights as an Alternative Endoscopic Light Source in Emergency Situations

Although the image quality from modern distal chip endoscopes is superior, limited mobility of the endoscopic tower prevents this technology from being used in inpatient and emergency departments. In these settings, otolaryngologists commonly use older flexible laryngoscopes with portable light sources. However, these light sources could malfunction. Smartphones are ubiquitous nowadays, and the smartphone's flashlight may be used alternatively to provide illumination when primary light malfunctions. This study compares the ability of flashlights from various smartphone models in providing adequate illumination for flexible laryngoscopy when compared to a commercially available portable light source. White wall and mucosal images were captured using Olympus P4 flexible scope and lights from the Stryker X8000 endoscopy tower light source, Storz 11301D3 portable light source (control), iPhone 4, iPhone 6, iPhone 8, iPhone X, Galaxy S6, and Galaxy S7. ImageJ was used to quantify pixel intensities with white and black standardized as 250 and 0, respectively. Student 2-tailed t test was used for analysis. The endoscopic tower outperformed all other light sources in all categories. The iPhone 4 and iPhone 6 consistently underperformed in comparison to the Storz 11301D3 portable light source (P < .05). Galaxy S6, Galaxy S7, and newer generation iPhone 8 and iPhone X provide comparable pixel intensities to Storz 11301D3 portable light. Smartphones incorporate different types of light-emitting diodes. Newer Galaxy and iPhone provide adequate illumination for the endoscopic assessment of the airway when compared to commercially available portable light source. However, one should always utilize the best commercially available light source in nonemergent cases.