Nasendoscopy is one of the most sophisticated methods used to evaluate the velopharyngeal valve during speech however unlike imaging with videofluroscopy, the uncertainties in this method have not been assessed. The purpose of this quality analysis study was to investigate the optical characteristics of 2 different nasendo-scopes commonly used in clinical practice. Results show that even relatively small differences in object-lens distance and variation in object position within the field of view cause significant changes in magnification and distortion. As such caution should be exercised when drawing clinical conclusions regarding VPI from quantitative and semi-quantitative analysis of nasendoscopic images.
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