Method errors recorded by inexperienced operators of the reflex microscope

The Reflex Microscope has become a standard instrument for the precision measurement of orthodontic record models. In this study, 31 individuals with no previous experience of the microscope were assessed for their precision at identifying well defined landmarks. Considerable initial variation existed in the precision of landmark identification, but despite only a limited training period, some of the novices tested achieved a high standard of precision. Mean errors were greatest in the z axis, i.e. along the axis of the eye, and astigmatism was common amongst those recording the greatest errors in this axis. A group of individuals who performed poorly initially, were retested after additional training and practice with the microscope. Method errors were significantly reduced for the majority of those retested, but the test apparatus identified two individuals for whom further measurement with the microscope would be inadvisable.