By photographing the corneal reflex in two positions of gaze and measuring the radius of curvature of the cornea it is possible to calculate the radius of rotation of the eye. The measurements obtained in this way showed a high correlation with refraction in a series of 80 eyes. The axial length obtained by this method was about 3 mm greater than that obtained by ultrasonographic or x-ray methods, and the reasons for the discrepancy are discussed.