Factors affecting the clinical testing of accommodative facility

A number of variables in the accommodation flipper test are thought to cont aminate the results: the time for naming symbols; the manual facility to ac tually operate the flippers; the minification or magnification of symbol ta rget size by the lenses; saccadic eye movements; and the relationship betwe en the accommodation stimulus and its response. With the exception of the l ast variable, all undesirable factors have been eliminated in a newly devel oped modified method of accommodation facility measurement. In this method, double measurement through piano and +/-2.00 D lenses, is executed. The av erage time in seconds per one cycle, taking only the accommodation into acc ount for a group of 43 children (age from 7 years 11 months to 9 years 11 m onths), is 3.7 monocularly and 8.5 binocularly and the average number of cy cles per minute in this group is 32.1 and 33.8 monocularly (for the dominan t and nondominant eye, respectively) and 22.6 binocularly. These results in sec/cycle do not differ considerably from results received by other author s, if one considers the time necessary for naming the digits, mechanically changing the lenses, saccadic eye movements etc., and even those results gi ven in cycles/minute do not differ either taking the wide ranges of standar d deviations into account. However, the method reported here reflects accom modation facility more precisely. Measurements were performed also with the hand held flipper. Comparison of results summarised above and those obtain ed with a hand held flipper demonstrates that the hand held flipper is not a good device to measure accommodative facility. Copyright (C) 1998 The Col lege of Optometrists. Published by Elsevier Science Ltd. All rights reserve d.