The relationship between visual acuity and luminance with soft contact lenses, compared with the same one obtained with issues or the maked eye, shows that activity decreases at the same rate as luninance is reduced, this result differs from what bad previously been found in comparing acuity with bard contact lenses and glasses. In the present case, soft lenses conform to the aspberical curve of the cornea, and therefore the eye soft contact lenses is not Related by spherical aberration, as in the case of bard contact lenses. At the soft lenses produce a some lower visual acuity but with adaptation, acuity improves and becomes equal or better, as evinced by measurements made after three months of wear.