[Refraction and its components in anisometropia].

PURPOSE To compare the individual means of ocular components of both eyes in patients with anisometropia; to correlate the differences of the components with refractive differences; and to identify the smallest number of factors that contain the same level of information expressed in the set of variables that influence refractive difference. METHODS An analytical transversal study was carried out in 77 patients with anisometropia of two or more dioptres seen at the Ophthalmologic Clinic, University Hospital, Nilton Lins Medical School, Manaus. RESULTS All participants were submitted to ophthalmologic examination which included objective and subjective cycloplegic refractometry, keratometry and ultrasound biometry. Data analysis comprised the following statistical models: univariate, multivariate, multiple and factorial regression analyses. CONCLUSIONS There were no significant differences in the comparison between the individual means of the ocular components. There was negative correlation between refractive difference and difference of axial length (r= -0.64; p<0.01) and weak negative correlation between refractive difference and crystalline lens power difference (r= -0.34; p<0.01). The analyzed variables reached 78% of the total variation of refractive difference. Three factors were identified for refractive differences: a) factor 1 (refraction, axial length); b) factor 2 (anterior chamber depth, cornea power), and c) factor 3 (crystalline lens power).