In vivo modification of refractive power of an intraocular lens implant

#This invention relates to in vivo modification of refractive power of an intraocular lens implant, and more specifically, the invention pertains to a method of changing the refractive power of an intraocular lens by the use of laser energy, generally after the lens has been implanted.

#It is well accepted that the insertion of an intraocular lens is the best solution for corrective vision after cataract surgery. Intraocular lenses and methods of inserting them are known to the art. For example, the U.S. Pat. No. 4,056,855, to Kelman, discloses an intraocular lens and a method of implanting same through an incision in the eye. The assembly includes a lens member and supporting wire initially in a disassembled condition and adapted to be introduced through a small incision in the eye. U.S. Pat. No. 4,608,049, also to Kelman, discloses an intraocular lens which may be inserted into the eye through a smaller incision in the cornea. U.S. Pat. No. 4,693,716, to MacKool, discloses an intraocular lens and implant including a lens centered on a lens axis. U.S. Pat. No. 4,813,954, to Siepser, discloses a compression, deformation, and dehydration method of fabrication and implantation of an expanse aisle, hydrogel intraocular lens. The problems associated with the foregoing patents include the fact that once the intraocular lens is implanted, it is not possible to change the refractive power of the implanted lens. Thus, when further correction becomes necessary, they must be replaced. U.S. Pat. No. 5,041,134, to O'Donnell, the inventor herein, discloses an intraocular lens assembly for implanting in the posterior chamber of a human eye after an extracapusular extraction. The intraocular lens assembly includes an optic holder having haptic elements for locating and positioning the optic holder in a fixed position within the posterior chamber of the eye and its optic lens releasably secured to the optic holder for interchange of different optic lenses as needed without removing the entire optic holder from the eye. This will allow changing of the refractive index of the implant without removal of the entire implant, but still the lens itself must be replaced. The Schachar U.S. Pat. No. 4,373,281, discloses a variable power intraocular lens and method of implanting same, the lens including a fluid expandable sac, which includes the lens portion, and a valve portion, that extends through sclera of the eye so that the fluid is subject to valve action which apparently can change the fluid expandable sac in order to vary the lens refraction. This patent requires the use of an electrode and microprocessor for changing the index of refraction of the intraocular lens to respond to desired parameters, but does nor disclose the use of the laser to make the fine adjustments in the refractive power of the lens.

#U.S. Pat. No. 4,669,466, to L'Esperance, discloses a method and apparatus for the analysis and correction of abnormal refractive errors of the eye. This invention discloses instrumentation for performing refraction-corrective surgery directly to the cornea. U.S. Pat. No. 4,665,913, also to L'Esperance, discloses another related method for ophthalmological surgery using a laser, but is limited to use upon the anterior surface of the cornea of the eye and not an intraocular lens implant. U.S. Pat. No. 4,676,790, to Kern, shows a method of manufacture and implantation of corneal inlays. A laser is used for milling into the surface of the cornea, to form a recess, so that when the implant is applied, its surface lies flush with the corneal membrane. This invention does not utilize lasers for changing the index, but simply provides lasers for use for inlaying an implant within the corneal surface.

#In referring to the drawings, FIG. 1 provides a schematic side view showing the laminations for the intraocular lens of this invention;

#FIG. 2 is a top plan view thereof;

#FIG. 3 is a schematic side view of a modification to the lens of FIG. 1;

#As previously reviewed, the concept of this invention is to allow usage of a laser device to modify the curvature, either at the front or back, of an optic lens, of the implant type, which may be fabricated from material that is subjected to degrees of hydration, whether the lens be formed totally or partially of a silicone, hydrogel, PMMA, collagen, or the like. Preferably, the modification can be made after the intraocular lens has been implanted or inserted into the eye.

#More specifically, this concept is to provide a way to fine tune the refractive power of the implant in vivo. The laser energy utilized could be at any normal and usable wave length such as 1064 nanometer, with the laser being directed and aimed at the surface, either the front or back, of the implant optic, or at its intermediate lamination, with the purpose of changing the curvature, and as a result, the refractive power of the implanted lens. In general, the implant lens might be coated with an inert surface material to facilitate a surface curvature change when exposed to the effect of the laser. This surface might be enclosed in order to confine resultant debris. Alternatively, the laser energy could be aimed at the haptic-lens implant junction, to alter the anterior-posterior position of the implant, relative to its haptic, and thus change the residual refractive error of the eye. Normally, the more anterior the location of the optic, the less plus power refractive power variation or change will be necessary.

#Finally, the implant could be used to altar the states of hydration of the optic and thus change the shape and hence the refractive power of the implant, through laser application.