The ultrasonic method of assessing the ocular components of refraction provides an observed axial length but no data on the lens surface powers. For many years the phakometric methods have been supplying a full data output on the lens surfaces and relying on a computed value for the axial length; the validity of the latter, however, has been challenged in the light of present-day techniques. A series of equations are presented in which the two techniques are combined to overcome some of the objections to phakometry yet maintain not only the lens data but also include the cardinal points of the eye optical system.
*Submitted February 12, 1968, for publication in the November, 1968, issue of the American Journal of Optometry and Archives of American Academy of Optometry.
This investigation was supported in part by a PHS research grant (NB05459) from the National Institute of Neurological Diseases and Blindness, U.S. Public Health Service.
†Optometrist, FSMC, Member of Faculty.
‡Ph.D., Member of Faculty. Fellow, American Academy of Optometry.
© 1968 American Academy of Optometry