From: Environmental and Genetic Factors Explain Differences in Intraocular Scattering Invest. Ophthalmol. Vis. Sci.. 2016;57(1):163-168. doi:10.1167/iovs.15-17897 Figure Legend: Path model for univariate analysis of a twin study. The observed phenotypes of twins 1 and 2 (scores 1 and 2) are represented in squares while latent factors that influence them are represented in circles (A, C, D, E). Additive (A) and dominant (D) genetics are correlated by a factor of 1.0 for MZ twins, and by 0.5 (A) and 0.25 (D), respectively, for DZ twins. Common environment (C) is fully correlated for all twins while unshared environment (E) is uncorrelated. Regression coefficients of the observed variables on the different latent factors are shown in lowercase: h is the regression coefficient of the additive genetic effect. (C, D) cannot be estimated simultaneously. Date of download: 10/3/2017 The Association for Research in Vision and Ophthalmology Copyright © 2017. All rights reserved.