Metrological Research on Test Method for Phoropters

A Phoropter is one of the most popular ophthalmic instruments used in current optometric practice, and the calibration is very important. However, there isn´t any normative test method suggested for phoropters in China. The research is to bring forward a new test method and try to unify its metrological calibration. Principle analysis and comparison are made among four feasible test methods. A test device is manufactured by using no-lens imaging technique, and experiments are made. Moreover, a special transfer support is designed to solve metrological calibration and traceability for quantity values. Result: Measuring range of the test device is from -25 m^-1 to +25 m^-1. The biggest indication error is not over 0.05 m^-1, and measurement uncertainty is about 0.08 m^-1 (k = 2). A new test method is brought forward to realize multi-parameter measurement for integrated phoropters. Besides, metrological calibration is solved and quantity values can be traced to the highest national standard for vertex power.