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Arch Ophthalmol. 2010 Dec;128(12):1555-60. doi: 10.1001/archophthalmol.2010.293.

Classifying stability of misalignment in children with esotropia using simulations.

Author information

1
Jaeb Center for Health Research, Tampa, FL 33647, USA. pedig@jaeb.org

Abstract

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.

PMID:
21149779
PMCID:
PMC3142011
DOI:
10.1001/archophthalmol.2010.293
[Indexed for MEDLINE]
Free PMC Article

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