SOURCES OF VARIANCE IN OCULAR MICROTREMOR

This study presents a preliminary investigation of the sources of vari ance in the measurement of ocular microtremor frequency in a normal po pulation. When the results from both experienced and relatively inexpe rienced operators are pooled, factors that contribute significantly to the total variance include the measurement procedure (p < 0.001), day -today variations within subjects (p < 0.001), and inter-subject diffe rences (p < 0.01). Operator experience plays a role in determining the measurement precision: the intra-subject coefficient of variation is about 5% for a very experienced operator, and about 14% for a relative ly inexperienced operator.