Distributions of measures of kappa angle and of cycloplegic refraction and their association are compared for groups of individuals with diagnosed exotropia and esotropia and with individuals having no manifest deviations. The esotropia group displayed an increased frequency of positive angles, an increased incidence of hypermetropia, and an increased association between large positive angles and hypermetropia. Relative to the nondeviation group, the exotropia group displayed an increased frequency of negative angles, a similar distribution for refractive errors, and an opposite association between refractive error and kappa angle.
Scott WE, Mash AJ. Kappa Angle Measures of Strabismic and Nonstrabismic Individuals. Arch Ophthalmol. 1973;89(1):18-20. doi:10.1001/archopht.1973.01000040020005