We have developed a method of computational simulation and estimation of thermo-optical distortions in solid-state laser rods, electro-optic shutters, and modulators, considering real heat-transfer conditions, anisotropic material properties, and an arbitrary cross-section shape of the element. Numerical investigations for Nd:YAG laser rods and potassium dihydrogen phosphate electro-optic shutters have been carried out, new results have been obtained, and known analytical solutions have been corrected.