as shown in fig1 and 2 , a lens system 100 according to an embodiment of the present invention includes an optical portion 102 for use in correcting presbyopia . in this example , the optical portion 102 is preferably circular , substantially circular or doughnut - shaped to act as a plus lens , but can be any shape desired . for instance , as shown in fig2 , the optical portion 102 - 1 can be semi - circularly shaped or crescent shaped . the optical portion 102 includes an opening 104 that can be centered or substantially centered in the optical portion 102 , or can be located anywhere in the optical portion 102 as appropriate . similarly , the optical portion 102 - 1 can be shaped such that the opening 104 - 1 is centered with respect to the optical portion 102 - 1 or such that the opening 104 - 1 is off - centered by a desired distance . the optical portion 102 ( 102 - 1 ), which can also be referred to as a lens , is preferably made of synthetic material , organic material , or a combination of both synthetic and organic material . additionally , the lens can be formed from any suitable material . for example the lens can be formed from collagen , copolymer collagen , polyethylene oxide , polypropylene , polyproledine or hydrogel , or cross - linked organic material such as collagen , hyaluronic acid , mucopolysacoharide , glycoprotein , polymethylmethacrylate or silicone , to name a few , or a combination thereof . further details of types of lens materials and structures are described in u . s . patent application of gholam a . peyman , entitled “ adjustable inlay with multizone polymerization ”, ser . no . 10 / 272 , 402 , filed oct . 17 , 2002 , the entire contents of which are herein incorporated by reference . it is noted that although this embodiment of the present invention includes a plus lens for the correction of presbyopia , the lens can be configured in any manner desired . for example , the lens can be a minus lens for correcting vision that is adversely affected by macular degeneration , or can have alternative shapes such as touric and the like for correcting astigmatism , or can be shaped and have suitable power and refractivity to correct for hyperopia , myopia and the like . as further shown in fig1 and 2 , the lens systems 100 includes haptics 106 and 108 have foot plates 110 and 112 , respectively , for mounting the lens systems 100 in the eye 116 . the diameter of the hole 104 in the lens 102 is preferably between about 0 . 5 mm to about 5 mm , but can have any suitable size . it is also noted that it is not necessary to have a hole 104 or opening in the lens 102 . for example , the hole 104 or opening can be replaced with a thin transparent portion that does not alter the path of light therethrough . in other words , the thin transparent portion can be nonrefractive or substantially nonrefractive . the thickness of the lens 102 is preferably within the range of at or about 0 . 025 mm to at or about 3 mm , and more preferably about 0 . 07 mm . however , the lens 102 can have any other suitable thickness . the diameter of the lens 102 is preferably within the range of at or about 0 . 5 mm to at or about 6 mm , but can be any suitable diameter . in addition , the lens 102 ( lens 102 - 1 ) is preferably curved ( instead of flat ) and has the center portion thicker than the edges . however , if desired , the edges can be thicker than the center . it is noted that the lens can have any shape that would improve the vision in the eye of a particular patient . furthermore , as shown in fig3 and 3a , the lens 102 can be configured as a diphractive lens 102 - 2 , if desired . for example , the lens can have grooves 102 - 21 at different diameters along the surface thereof . these grooves , along with the multiple zones 102 - 22 separated by the grooves , act as prisms in the diphractive technology discussed above . specifically , the multiple zones 102 - 22 can be recessed , or bumps , and have different refractive powers , such as + 3 diopeters , + 6 diopters , or any other suitable power which can enable the lens to correct for hyperopia , myopia , presbyopia , or astigmatism . as shown in fig4 and 5 , the edges of the lens portion can be configured to effect a gradual change in the refractive power thereof . for example , as shown in fig4 , the lens 102 can be configured as lens 102 - 3 having a first portion 102 - 31 that can have little or no refractive power , and a second portion 102 - 32 that has a varying thickness or shape so that its refractive power gradually changes . as shown in fig5 , the semicircularly shaped lens 102 - 1 shown in fig2 can be configured as lens 102 - 4 having first portions 102 - 41 that can have little or no refractive power , and a second portion 102 - 42 that has a varying thickness or shape so that its refractive power gradually changes . for a further discussion of this type of configuration , see copending u . s . application ser . no . 10 / 356 , 730 entitled “ subepithilial implant and method of treatment of presbyopian and other refractive errors ”, the entire contents of which are incorporated herein by reference . furthermore , as shown in fig6 - 8 , the edges of the lenses 102 , 102 - 1 and all other lenses discussed above , as well as the haptics 106 and 108 , can be pigmented or painted with a suitable light absorbing material 103 of a suitable color , such as black , to prevent light reflection and glare . a more detailed description of glare free iols is set forth in u . s . pat . nos . 6 , 277 , 146 and 6 , 280 , 471 both to peyman et al ., which are incorporated herein by reference . as shown in fig9 , the lens system 100 can be positioned either in the anterior chamber 118 of the eye 116 in front of the iris 120 and behind the cornea 122 . alternatively , as shown in fig1 , the lens system 100 can be positioned in the posterior chamber 124 of the eye 116 behind the iris 120 and in front of the natural lens 124 or another artificial lens ( not shown ). specifically , the lens system 100 can be positioned such that the lens 102 ( 102 - 1 ) is spaced from the front of the natural lens 124 ( or artificial lens ), or can be positioned in contact with the front of the natural lens 124 ( or artificial lens ) as a piggyback lens . also , the lens system 100 can be implanted in place of the natural lens 124 of the eye 116 as shown in fig1 . the lens is coupled to the interior portion of the eye using haptics having a footplate or with any type of haptics or in any manner desired . for a further discussion of acceptable haptics , see u . s . pat . nos . 6 , 277 , 146 and 6 , 280 , 471 discussed above . as shown in fig3 - 6 and 8 - 11 , the lens 102 ( and all the variations discussed above ) is positioned with the radial center of the lens 102 positioned to coincide with the main optical axis of the eye 116 . the positioning allows the center portion to be used for far vision and the outer lens portion to be used for near vision , such as reading . since there is no refractive portion in the center , there is no correction for far vision , while the outer portion of the lens corrects for presbyopia or any other vision problems desired . additionally , the lens shape and size can be altered ( i . e ., the lens can increase in size and / or volume or decrease in size and / or volume when exposed to the appropriate energy or altered in a desired manner ) as described in u . s . patent application of gholam a . peyman entitled “ a method and apparatus for correcting the refraction of an intraocular lens after implantation in the eye ”, ser . no . 10 / 197 , 885 , filed jul . 19 , 2002 , and u . s . pat . no . 6 , 436 , 092 to gholam a . peyman entitled “ adjustable universal implant blank for modifying corneal curvature and methods of modifying corneal curvature therewith ”, the entire contents of both of which are herein incorporated by reference . another embodiment of a lens system 200 for correcting presbyopia is shown in fig1 - 15 . specifically , lens system 200 includes an optical portion 202 that can be preferably ring or doughnut shaped and has an opening 204 therein . however , the lens 202 can have any desired shape and the features of lenses 102 , 102 - 1 and their variations discussed above , and can be made of any of the materials discussed above . the lens 202 can have no refractive power or any degree of refractive depending on the application in which it is used . the lens can also have diphractive optical characteristics , and thus can be made very thin . furthermore , the lens 202 can be adjustable by light as described in u . s . pat . no . 6 , 436 , 092 to peyman , the entire contents of which are incorporated herein by reference . in addition , as discussed above and is shown in fig9 - 11 , the lens can be a piggy - back type lens , or can be placed in the anterior chamber of the eye 116 , or in the posterior chamber of the eye 116 along with or in place of the natural lens 124 or another artificial lens in the eye 116 . as will now be further described , the lens system 200 can be made adjustable so that the hole 204 in the center of the lens 202 can be increased or decreased in size . specifically , as shown in fig1 , the lens 202 has a tube arrangement 206 and 208 that can receive the ends of haptics 210 and 212 , respectively . similar to haptics 106 and 108 discussed above , haptics 210 and 212 have foot plates 214 and 216 , respectively . as indicated , the ends of the haptics 210 and 212 can be received in the tube arrangements 206 and 208 or the pulled out of the tube arrangements 206 or 208 to increase the overall lens of the lens system 200 . furthermore , in order to adjust the position of the opening 204 with regard to the optical axis of the eye 116 , the lens 202 can be moved in a upward direction along arrow a so that the end of haptics 210 is received into tube arrangement 206 while the end of haptics 212 is moved in a direction out of tube arrangement 208 . likewise , the lens 202 can be moved down in a direction along arrow b so that the end of haptic 212 is further received into tube arrangement 208 while allowing the end of haptic 210 to move in the direction out of tube arrangement 206 . this movement can be effected by inserting a small surgical tool into an opening in the eye 116 , and then using the tool to move the haptics 210 and 212 as appropriate . furthermore , an adhesive can be used , if desired , to more permanently attach the haptics 210 and 212 to the lens 202 once the lens has been positioned as appropriate and the desired overall length of the lens system 200 has been established . as further shown in fig1 - 15 specifically , the lens 202 can be configured as lens 202 - 1 which includes a top portion 202 - 11 and a bottom portion 202 - 12 . as indicated , the lens 202 - 1 ( as well as lens 202 shown in fig1 ) can have a glare - free material 203 on its edges , such as pigmented edge or any of the glare free materials discussed above . accordingly , by moving the top portion 202 - 11 and bottom portion 202 - 12 up or down with respect to the haptics 210 - 1 and 212 - 1 as shown in fig1 , the portions 202 - 11 and 202 - 12 of the lens 202 - 1 can be moved away from each other and therefore increase the size of opening 204 - 1 . this movement can be effected by inserting a small surgical tool into an opening in the eye 116 , and then using the tool to move the portions 202 - 11 and 202 - 12 as appropriate . alternatively , as shown in fig1 , the upper portion 202 - 11 and lower portion 202 - 12 can be moved closer to each other to make the opening 204 - 1 smaller . as further discussed above , the lens portions 202 - 11 and 202 - 12 can have no refractive properties or any refractive properties as discussed above . in addition , as shown in fig1 , the haptics 210 , 210 - 1 , 212 and 212 - 1 and engaging portions of the lens 204 or 204 - 1 can have any particular configuration . for example , the haptics 210 , 210 - 1 , 212 and 212 - 1 need not be tube - shaped . rather , they can be slotted , or the haptics and engaging portions of the lens 204 or 204 - 1 have a tongue and groove arrangements or any other type of arrangement that allows for mating and movement between the lens and the haptics . furthermore , the anterior of the haptics 210 , 210 - 1 , 212 and 212 - 1 can have a serrated portion 213 which can mate with a serrated portion 205 of the engaging portions of the optic lens 204 - 1 so as to allow the mating portion to gradually mate with the haptics as shown in fig1 . while certain embodiments have been chosen to illustrate the invention , it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims .
an intraocular lens for modifying the refractive abilities of a natural lens or an existing artificial lens in an eye to correct for vision disorders such as presbyopia , myopia , hyperopia or astigmatism . specifically , the lens system can be configured so that it does not effect far vision , while effecting near vision using a plus lens to correct for presbyopia . the lens system includes a lens portion and fastening members , with the lens portion being movably secured to at least one of the fastening members so that the position of the lens portion can be modified with respect to the optical axis , and the overall length of the lens system can be increased or decreased .