Four methods (by means of Smirnova-Korniushina's aberrometer; with the help of aberroscope--Cherning's lattice; by presenting a figure of a cross; and by automatic refractometry through different portions of the pupil) were used for studying aberration of the optic system of the eye in 490 persons. Among them, 37 were healthy persons, 27--patients with ametropia of moderate degree, 24--with high myopia, 9--with astigmatism above 3.0 D, 16--with monocular diplopia, 327--with keratoconus, 7--with scars of the cornea, 21--with initial cataract, 47--after keratotomy. In norm and in ametropia to 6.0 D, a histogram of refraction distribution by the pupil has a small disperse and a pronounced peak, the Cherning's lattice is straight. In high myopia, the disperse of refraction increases, the peak is slightly pronounced, the lattice is curved along the margins. In astigmatism, the disperse of refraction is great, but there can be peaks. The whole lattice is curved. In monocular diplopia, two more peaks can be seen on the histogram. The lattice is greatly curved. In keratoconus, aberrometry without correction is possible only at the initial stage and shows a rather mixed picture. The histogram of refraction represents a low irregular row. In aberroscopy, the bands are greatly curved, frequently overstep the bounds of the frame that itself looses a form of a circle, becomes oval or polygonal. Contact correction improves the aberration picture considerably. In scars of the cornea, the lattice is distorted and infrequently repeats their forms. In initial cataract, the course of the bands becomes interrupted and rounded spots appear between them.(ABSTRACT TRUNCATED AT 250 WORDS)