2011-21: When may variation in deviations of strabismus be considered as real change?
A guiding value can be helpful for clinicians to determine whether measured differences in strabismus deviation are likely to represent a true change. This cross-sectional prospective study is developed to investigate inter-examiner variability of the alternate prism and cover test (APCT) measurements of ocular deviation at near and distance fixation, and to compare variability between adults/teenagers and children. All patients with strabismus, visiting the orthoptic department of the Rotterdam Eye Hospital will be asked to participate. The main study parameters are inter-examiner difference in ocular deviation at near and distance fixation and limits of agreement at 95% level.