The refractometry is used for not only technical but biological and medical examinations. Among the letter ophthalmological investigations are predominant. Human eye optical system is examined by refractometry for clinical and research aims. Ergophthalmological investigations are more precise than usual clinical examinations and they are needed in thin technology which is not worked out for the present. Especially such precise and thin measurings of human eye corneal astigmatism are extremely necessary for study of visual capacity and fatigue in all the kinds of visual load work particularly precise visual work and work with display units.