Irregular astigmatism of the eye: effect of correcting lenses

Experiments to test the grating acuity of the eye in different meridians reveal the prevalence of irregular refraction, or astigmatism as it is usually called. Comparisons are made between the ordinary subjective findings and tests made on gratings. The effects of changes of lens power on the acuity in different meridians of the eye are considered. A redistribution of the acuity over the several meridians during accommodation is indicated.