Correction of Presbyopia with Ultrashort Pulse Laser (Crystalline Lens Surgery)

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Princeton University Invention # 05-2211



Presbyopia is a natural age-related process that affects everyone from the age of 45 on, regardless of whether or not they have always had normal vision or have suffered from myopia, hyperopia or astigmatism. Presbyopia is the increasing inability to maintain near objects in focus. People with presbyopia have to hold reading materials at arms¿ length to be able to focus on the image.  Currently there is no surgical correction for presbyopia available that directly restores the accommodative ability of the native crystalline lens.


Researchers in the Department of Mechanical and Aerospace Engineering, Princeton University have developed a device and procedure with the potential for correcting presbyopia. This invention will allow for minimally invasive laser surgery of the lens of the eye to correct for presbyopia. The invention uses a femtosecond laser, together with proprietary software  to precisely remove, by photablation, prescribed portions of the eye lens, with the added possibility of replacing the removed parts of the lens with a specially developed polymer with suitable biomechanical and refractive properties. The use of femtosecond lasers provide high intensity light at very low energy levels so that the ablation proceeds very precisely, with negligible heating and collateral trauma.


Although the mechanisms of human accommodation remain controversial, most evidence supports the Helmholtz model¹ of accommodation where contraction of the ciliary muscle releases zonal tension on the lens capsule.  This allows the normal elastic properties of the lens to cause the anterior radius of curvature to decrease. Since volumetric and morphological conditions exacerbate presbyopia by changing biomechanical properties of the lens as well as the efficacy of the zonular mechanism, it is possible that decreasing lens volume would help to restore a normal accommodative amplitude. The removal of lens material using photoablation with femtosecond lasers would give a methodology for altering the lens optics and mechanics to restore accommodation.


Preliminary in vitro data is very encouraging and further work is ongoing.



Selected Publications:


¹Helmholtz, H., ¿Treatise on Physiologic Optics¿, Translated from the 3rd German

Southall. J.P., ed. New York: Dover Publications (1962).

Glasser A. and Kaufman P.L., ¿The Mechanism of Accommodation in Primates¿, Ophthalmology, 106: 863-872 (1999).


Brown N., ¿The Shape of the Len Equator¿, Experimental Eye Research, 19:571-576 (1974).




Princeton University is currently seeking industrial collaborators to assist in the development and commercialization of this invention.  Patent protection is pending.


For more information on Princeton University Invention # 05-2211 please contact:



                        Laurie Tzodikov

                        Office of Technology Licensing and Intellectual Property

                        Princeton University

                        4 New South Building

                        Princeton, NJ 08544-0036

                        (609) 258-7256

                        (609) 258-1159 fax


Patent Information:
For Information, Contact:
Laurie Tzodikov
Licensing Associates
Princeton University
Peter Hersh
Szymon Suckewer
Alexander Smits
Richard Register
Clarence Schutt
Anatoli Morozov
Gary Kunkel