OBJECTIVE: To determine the sensitivity and specificity of several classification rules for stability and instability of angle in childhood esotropia. METHODS: We conducted 10 000 Monte Carlo simulations of participants with no actual change in angle of esotropia during follow-up, where "observed" changes in ocular alignment were sampled from a distribution of measurement errors for the prism and alternate cover test. Additional simulations were conducted for a range of "true" changes (1.0, 2.5, 4.2, 5.0, 7.5, and 10.0 prism diopters [PD] per visit) with up to 10 follow-up visits. We then estimated sensitivities and specificities for specific rules for retrospectively classifying stability (all measurements within 0, 5, 10, or 15 PD) and instability (≥2 measurements differing by ≥10 PD, etc) across a fixed number of visits. Results were extended to classifying ocular alignment stability and instability prospectively based on a varying number of measurements. RESULTS: For a series of 4 measurements, the rules that optimized sensitivity and specificity were "all measurements within 5 PD" for stability and "at least 2 measurements differing by 15 PD or more" for instability. For a series of 3 measurements, all 3 measurements needed to be identical to confirm stability. CONCLUSIONS: We derived definitions of stability and instability in childhood esotropia using estimates of actual measurement error that may be useful for clinical practice and for future clinical studies of esotropia.
OBJECTIVE: To determine the sensitivity and specificity of several classification rules for stability and instability of angle in childhood esotropia. METHODS: We conducted 10 000 Monte Carlo simulations of participants with no actual change in angle of esotropia during follow-up, where "observed" changes in ocular alignment were sampled from a distribution of measurement errors for the prism and alternate cover test. Additional simulations were conducted for a range of "true" changes (1.0, 2.5, 4.2, 5.0, 7.5, and 10.0 prism diopters [PD] per visit) with up to 10 follow-up visits. We then estimated sensitivities and specificities for specific rules for retrospectively classifying stability (all measurements within 0, 5, 10, or 15 PD) and instability (≥2 measurements differing by ≥10 PD, etc) across a fixed number of visits. Results were extended to classifying ocular alignment stability and instability prospectively based on a varying number of measurements. RESULTS: For a series of 4 measurements, the rules that optimized sensitivity and specificity were "all measurements within 5 PD" for stability and "at least 2 measurements differing by 15 PD or more" for instability. For a series of 3 measurements, all 3 measurements needed to be identical to confirm stability. CONCLUSIONS: We derived definitions of stability and instability in childhood esotropia using estimates of actual measurement error that may be useful for clinical practice and for future clinical studies of esotropia.
Authors: Stephen P Christiansen; Danielle L Chandler; Jonathan M Holmes; Robert W Arnold; Eileen Birch; Linda R Dagi; Darren L Hoover; Deborah L Klimek; B Michele Melia; Evelyn Paysse; Michael X Repka; Donny W Suh; Benjamin H Ticho; David K Wallace; Richard Grey Weaver Journal: Ophthalmology Date: 2008-10-29 Impact factor: 12.079
Authors: Roy W Beck; Maureen G Maguire; Neil M Bressler; Adam R Glassman; Anne S Lindblad; Frederick L Ferris Journal: Ophthalmology Date: 2007-10 Impact factor: 12.079