Abstract:
The system is able to correct the spherical and cylindrical power as well as other aberrations of the optical pathway of both eyes of a person eliminating the need for multiple heavy glass lenses and mirrors. For correcting the refractive errors, the above described system is equipped with a diachroic mirror interposed in front of the system, to divert part of the light reflecting from the pupil to a Shack-Hartman wave front sensor.

Description:
This application is a continuation-in-part of application Ser. No. 11/426,224 entitled “External Lens Adapted to Change Refractive Properties”, filed Jun. 23, 2006, now U.S. Pat. No. 7,993,399, which is a continuation-in-part of application Ser. No. 11/259,781, entitled “Intraocular Lens Adapted for Accommodation Via Electrical Signals”, filed Oct. 27, 2005, now abandoned the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     A normal emetropic eye includes a cornea, lens and retina. The cornea and lens of a normal eye cooperatively focus light entering the eye from a far point, i.e., infinity, onto the retina. However, an eye can have a disorder known as ametropia, which is the inability of the lens and cornea to focus the far point correctly on the retina. Typical types of ametropia are myopia, hypermetropia or hyperopia, and astigmatism. 
     A myopic eye has either an axial length that is longer than that of a normal emetropic eye, or a cornea or lens having a refractive power stronger than that of the cornea and lens of an emetropic eye. This stronger refractive power causes the far point to be projected in front of the retina. 
     Conversely, a hypermetropic or hyperopic eye has an axial length shorter than that of a normal emetropic eye, or a lens or cornea having a refractive power less than that of a lens and cornea of an emetropic eye. This lesser refractive power causes the far point to be focused in back of the retina. 
     An eye suffering from astigmatism has a defect in the lens or shape of the cornea. Therefore, an astigmatic eye is incapable of sharply focusing images on the retina. 
     An eye can also suffer from presbyopia. Presbyopia is the inability of the eye to focus sharply on nearby objects, resulting from loss of elasticity of the crystalline lens. 
     Optical methods are known which involve the placement of lenses in front of the eye, for example, in the form of glasses or contact lenses, to correct vision disorders. A common method of correcting myopia is to place a “minus” or concave lens in front of the eye in order to decrease the refractive power of the cornea and lens. In a similar manner, hypermetropic or hyperopic conditions can be corrected to a certain degree by placing a “plus” or convex lens in front of the eye to increase the refractive power of the cornea and lens. Lenses having other shapes can be used to correct astigmatism. Bifocal lenses can be used to correct presbyopia. The concave, convex or other shaped lenses are typically configured in the form of glasses or contact lenses. 
     SUMMARY 
     In one embodiment, a lens system is provided. The lens system includes a lens adapted to be positioned along the main optical axis of the eye and a control unit. The control unit is operable with the lens to alter the focal length of the lens based at least partly upon a condition, such that the lens alters light rays and focuses the rays on the retina of the eye. 
     In another embodiment, a lens is provided. The lens includes a chamber adapted to house a substance. The lens is adapted to be positioned externally and relative to an eye and coupled to a control unit. The control unit is operable to control the focal length of the lens by influencing the substance, such control of the focal length altering light rays and focusing the light rays on the retina of the eye. 
     In another embodiment, a control unit is provided. The control unit includes an electronic circuit. The control unit is coupled to a lens, which includes a chamber adapted to house a substance. The lens is adapted to be positioned externally and relative to an eye. The electronic circuit is operable to control the focal length of the lens, such control of the focal length altering light rays and focusing the light rays on the retina of the eye. 
     Additional features and advantages are described herein, and will be apparent from, the following Detailed Description and the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a side elevational view in section taken through the center of an eye showing the cornea, pupil, crystalline lens, and capsular bag. 
         FIG. 2  is a side elevational view in section of the eye shown in  FIG. 1  showing the capsular bag after removal of the crystalline lens. 
         FIG. 3  is a side elevational view in section of the eye shown in  FIG. 2  showing the treatment of the interior of the capsular bag with a liquid to prevent capsular opacification. 
         FIG. 4  is a side elevational view in section of the eye shown in  FIG. 3  showing placement of a replacement lens into the capsular bag. 
         FIG. 5  is a side elevational view in section of the eye shown in  FIG. 3  in which a replacement lens is positioned in the capsular bag and a fluidic system and remote power unit are positioned in the posterior chamber. 
         FIG. 6  is a flow chart of the process of accommodation in accordance with one embodiment of the present invention. 
         FIG. 7  is a flow chart of the process of accommodation in which the fluidic system includes a pressure sensor for sensing the pressure in at least one of the chambers in accordance with one embodiment of the present invention. 
         FIG. 8  is a side elevational view in section of the eye shown in  FIG. 3  in which a replacement lens is positioned in the capsular bag and a power unit is positioned in the posterior chamber. 
         FIG. 9  is a flow chart of the process of accommodation in response to electrical signals in accordance with one embodiment of the present invention. 
         FIG. 10  is a side view in section of another embodiment of the present invention, showing the adjustable lens positioned relative to the eye. 
         FIG. 11  is a side view in section of another embodiment of the present invention, showing the adjustable lens as a contact lens. 
         FIGS. 12 and 13  illustrate another embodiment of the present invention in which a device is shown that is capable of correcting all low order aberration of the refractive errors. 
     
    
    
     DETAILED DESCRIPTION 
     In various embodiments, a lens capable of accommodation in response to electrical signals is provided. The lens can be placed at any suitable location along the optical path of an eye, including but not limited to within the capsular bag, in place of the capsular bag, within the posterior chamber or on, in or behind the cornea. Further, it should be noted that any suitable section of the capsular bag can be removed, including but not limited to an anterior portion or a posterior portion around the main optical axis of the eye. The lens is preferably coupled to a fluidic pumping system which is also coupled to a control system which preferably includes a power source and a signal generation unit. 
     Referring initially to  FIG. 1 , a normal eye  10  has a cornea  12 , an iris  14 , and a crystalline lens  16 . The crystalline lens  16  is contained within a capsular bag  18  that is supported by zonules  20 . The zonules  20 , in turn, are connected to the ciliary muscle  22 . According to Helmholz&#39;s theory of accommodation, upon contraction of the ciliary muscle  22 , the tension on the zonules  20  is released. The elasticity of the lens causes the curvature of the lens  16  to increase, thereby providing increased refractive power for near vision. Conversely, during dis-accommodation, the ciliary muscle  22  is relaxed, increasing the tension on the zonules  20  and flattening the lens  16  to provide the proper refractive power for far vision. 
     If the electrically accommodating lens is to be positioned within the capsular bag and, thus, replace the crystalline lens, a suitable first step is to remove the existing lens. As illustrated in  FIG. 2 , the lens is preferably removed using any technique which allows removal of the lens through a relatively small incision, preferably about a 1-2 mm incision. The preferred method is to create a relatively small incision  24  in the cornea  12  and then perform a capsulorhexis to create an opening  26  into the anterior side  28  of the capsular bag  18 . An ultrasonic probe  30  is inserted into the capsular bag  18  through the opening  26 . The probe&#39;s vibrating tip  32  emulsifies the lens  16  into tiny fragments that are suctioned out of the capsular bag by an attachment on the probe tip (not shown). Alternatively, the lensectomy may be performed by laser phacoemulsification or irrigation and aspiration. 
     Once the crystalline lens  16  has been removed, the capsular bag  18  can be treated to help prevent a phenomenon known as capsular opacification. Capsular opacification is caused by the proliferated growth of the epithelial cells on the lens capsule. This growth can result in the cells covering all or a substantial portion of the front and rear surfaces of the lens capsule, which can cause the lens capsule to become cloudy and thus adversely affect the patient&#39;s vision. These cells can be removed by known techniques, such as by scraping away the epithelial cells; however, it is often difficult to remove all of the unwanted cells. Furthermore, after time, the unwanted cells typically grow back, requiring further surgery. To prevent capsular opacification, the capsular bag  18  is preferably treated to eliminate the proliferated growth of epithelial cells, as described below. 
     As seen in  FIG. 3 , one method of treating the epithelial cells to prevent capsular opacification is to use a cannula  34  to introduce a warm liquid  36  (preferably about &lt;60° C.) into the capsular bag  18 , filling the capsular bag  18 . The liquid contains a suitable chemical that kills the remaining lens cells in the capsular bag and also cleans the interior of the capsular bag. Suitable chemicals, as well as other suitable methods of treatment that prevent capsular opacification are disclosed in U.S. Pat. No. 6,673,067 to Peyman, which is herein incorporated by reference in its entirety. 
     As shown in  FIG. 4 , a replacement lens  38  is then positioned within the capsular bag  18 . Preferably, the lens  38  can be folded or rolled and inserted through the incision in the capsular bag  18 ; however, the lens  38  can be rigid and/or can be inserted through a larger second incision in the capsular bag  18  or the initial incision, possibly after the initial incision is widened, or in any other suitable manner. Preferably the lens  38  varies its focal length in response to changes in fluidic pressure within the lens made in accordance with electrical signals; however the lens  38  can change its index of refraction or alter its focal length in any other suitable manner. Since the capsular bag  18  is still in place, the capsular bag can still assist in accommodation; however, it is not necessary for capsular bag  18  to assist with accommodation. The lens, as shown in  FIG. 5 , preferably includes two chambers  40  set on opposite sides of a substrate  42  and covered with a flexible membrane  44 ; however, the lens can have one or any other suitable number of chambers. Preferably, the two chambers  40  contain a fluid  46 , and preferably the fluid  46  is a sodium chromate solution; however, if desired, one or more of the chambers can contain something other than a fluid or the chambers can contain different fluids or different sodium chromate solutions. The substrate  42  is preferably glass; however, the substrate  42  can be any suitable material. Preferably, the flexible membrane  44  is a biocompatible material; however, the flexible membrane can be any suitable material. 
     Preferably, the fluidic pressure within the chambers  40  can be altered using a fluidic system  48  which includes a miniature fluidic pressure generator (e.g., a pump or any other suitable device), a fluid flow control device (e.g., a valve or any other suitable device), a control circuit and a pressure sensor; however, the fluidic pressure can be altered in any suitable manner. Further, if desired, a fluidic system  48  does not need a pressure sensor. When subjected to electrical signal, the electronic control circuit of the fluidic system  48  controls the valves and pumps to adjust the fluidic pressure in one or more of the chambers  40 . Preferably, the fluidic pressure is adjusted by pumping fluid in or releasing a valve to allow fluid to flow out and back into the system  48 ; however, the fluidic pressure can be adjusted by pumping fluid out or in any other suitable manner. As a result, the shape and the focal length of the lens  38  is altered, providing accommodation. Lenses that similarly change focal length in response to fluidic pressure changes made in accordance with electrical signals are described in greater detail in “Integrated Fluidic Adaptive Zoom Lens”,  Optics Letters , Vol. 29, Issue 24, 2855-2857, December 2004, the entire contents of which is hereby incorporated by reference. 
     As shown in  FIG. 5 , fluidic system  48  is preferably positioned in the posterior chamber  50 ; however, the fluidic system  48  can be positioned outside the eye, within the sclera, between the sclera and the choroids or any other suitable location. Further, the fluidic system  48  is preferably positioned such that it is not in the visual pathway. A tube  52  fluidly connects the lens  38  and the fluidic system  48 . Preferably, the tube  52  passes through a small incision in the capsular bag  18  near the connection of the zonules  20  and the capsular bag  18 ; however, the tube  52  can pass through the capsular bag in any suitable location. 
     Preferably, fluidic system  48  includes a power source which is preferably rechargeable through induction or other suitable means such as generating and storing electrical energy using eye and/or head movement to provide the energy to drive the generator; however, fluidic system  48  can be connected to a remote power source  54  as shown in  FIG. 5  or to any other suitable power source. Preferably, the remote power source  54  is located in the posterior chamber  50 ; however, the remote power source  54  can be positioned outside the eye (e.g., under the scalp, within a sinus cavity, under the cheek, in the torso or in any other suitable location), within the sclera, between the sclera and the choroids or any other suitable location. Further, the remote power source  54  is preferably positioned such that it is not in the visual pathway. The remote power source  54  is preferably electrically coupled to the fluidic system  48  by electrically conductive line  56 ; however, the remote power source  54  can be coupled to the fluidic system  48  in any suitable manner. Further, the remote power source  54  preferably includes a signal generator which can supply control signals to the fluidic system  48  via electrically conductive line  56 ; however, the remote power source  54  can be without a signal generator, if desired, or can supply control signals to the fluidic system  48  in any suitable manner. Similar remote power sources are described in more detail in U.S. Pat. No. 6,947,782 to Schulman et al. which is herein incorporated by reference in its entirety. 
     Preferably, the remote power source  54  is coupled to a sensor  58  by electrically conductive line  60 ; however, the remote power source  54  can be coupled to sensor  58  in any suitable manner. The sensor  58  is preferably a tension sensor positioned on the zonules  20  so that the sensor  58  detects the amount of tension present in the zonules  20 ; however, the sensor  58  can be a wireless signal sensor, a neurotransmitter sensor, a chemical sensor, a pressure sensor or any other suitable sensor type and/or can be positioned in or near the ciliary muscle  22 , at or near the nerve controlling the ciliary muscle  22 , in the capsular bag  18  or in any other suitable location. Preferably, the sensor  58  detects the eye&#39;s attempt to cause its lens to accommodate; however, the sensor  58  can detect a manual attempt to accommodate the lens  38  (e.g., input through a wireless controller) or any other suitable input. The information detected at the sensor  58  is relayed to the remote power source  54  via line  60 , and the signal generator of the remote power source  54  generates a signal in accordance with the information. The signal is sent to the fluidic system  48 , which adjusts the fluidic pressure in one or more of the chambers  40  accordingly. Thus, the eye&#39;s natural attempts to focus will result in accommodation of lens  38 . Response of lens  38  may vary from that of the natural lens; however, the neural systems which control the ciliary muscle  22  (and therefore the tension on the zonules  20 ), are provided with feedback from the optic nerve and visual neural pathways. As a result, the neural system can learn and adjust to the characteristics of the lens  38 . 
     The process of accommodation in accordance with one embodiment is shown in  FIG. 6 . At step  600 , the eye attempts to refocus at a different distance, and thus changes the tension on the zonules. At step  610 , a tension sensor detects the new tension level and relays the information to a control unit. The control unit preferably includes a remote power source and a fluidic system; however, the control unit can include any suitable devices. At step  620 , the control unit determines the correct adjustment to be made to the fluidic pressure in at least one chamber of a fluidic lens in response to the tension sensor information. At step  630 , the control unit makes the determined fluidic pressure adjustment and the process repeats at step  600 . 
     Another process of accommodation in accordance with another embodiment in which the fluidic system includes a pressure sensor for sensing the pressure in at least one of the chambers is shown in  FIG. 7 . At step  700 , a user sends a signal to refocus his or her eye at a different distance. Preferably, the signal is sent wirelessly; however, the signal can be sent in any suitable manner. Further, the signal preferably includes information corresponding to the desired different distance; however, the signal can include information indicating only that the desired distance is closer or farther or any other suitable information. At step  710 , a sensor detects the signal and relays the information to a control unit. The control unit preferably includes a remote power source and a fluidic system; however, the control unit can include any suitable devices. At step  720 , the control unit determines a new fluidic pressure level to be created in at least one chamber of a fluidic lens in response to the sensor information. At step  730 , the control unit increases or decreases, as appropriate given the current fluidic pressure as determined by the pressure sensor, the fluidic pressure in the chamber. At step  740  it is determined whether the desired fluidic pressure is equal to the pressure sensed by the pressure sensor. If the desired fluidic pressure is equal to the pressure sensed by the pressure sensor, at step  750 , the lens is accommodated and the process repeats at step  700 . If the desired fluidic pressure is not equal to the pressure sensed by the pressure sensor, the process repeats at step  730 . 
       FIG. 8  illustrates an alternative accommodating lens  62 . Lens  62  responds to electrical stimulation by changing its focal length. Similar to lens  38 , lens  62  is preferably placed within the capsular bag  18 ; however, the lens  62  can be placed in the posterior chamber  50 , in place of the capsular bag  18 , within the cornea  12 , on the surface of the eye or in any other suitable location. Further, it should be noted that any suitable section of the capsular bag can be removed, including but not limited to an anterior portion or a posterior portion around the main optical axis of the eye. If the lens  62  is placed within the capsular bag  18 , the capsular bag can assist with accommodation; however, it is not necessary for the capsular bag  18  to assist with accommodation. Lens  62  may have one or more chambers that are at least partly filled with a fluid or other substance; however, lens  62  is not required to have a chamber. 
     Preferably, lens  62  is a fluid lens that alters its focal length by changing its shape; however lens  62  can be any suitable type of lens and can change its focal length in any suitable manner. The lens  62  preferably includes two immiscible (i.e., non-mixing) fluids of different refractive index (or other suitable optical property); however, the lens  62  is not required to include two immiscible fluids of different refractive index. Preferably, one of the immiscible fluids is an electrically conducting aqueous solution and the other an electrically non-conducting oil, contained in a short tube with transparent end caps; however, the immiscible fluids can be any suitable fluids and can be contained in any suitable container. The internal surfaces of the tube wall and one of its end caps are preferably coated with a hydrophobic coating that causes the aqueous solution to form itself into a hemispherical mass at the opposite end of the tube, where it acts as a spherically curved lens; however, the hydrophobic coating is not required and, if present, can be arranged in any suitable manner. Further, the coating can include any suitable material, including hydrophilic substances. 
     Preferably, the shape of the lens  62  can be adjusted by applying an electric field across the hydrophobic coating such that it becomes less hydrophobic (a process called “electrowetting” that results from an electrically induced change in surface-tension); however, the shape of the lens  62  can be adjusted by applying an electric field across any suitable portion of the lens  62 . Preferably, as a result of this change in surface-tension, the aqueous solution begins to wet the sidewalls of the tube, altering the radius of curvature of the meniscus between the two fluids and hence the focal length of the lens. Increasing the applied electric field can preferably cause the surface of the initially convex lens to become less convex, substantially flat or concave; however increasing the applied electric field can cause the surface of the lens to change in any suitable manner. Preferably, decreasing the applied electric field has the opposite effect, enabling the lens  62  to transition smoothly from being convergent to divergent, or vice versa, and back again repeatably. 
     The lens  62  can measure 3 mm in diameter by 2.2 mm in length; however the lens  62  can have any suitable dimensions. The focal range of the lens  62  can be any suitable range and can extend to infinity. Further, switching over the full focal range can occur in less than 10 ms or any other suitable amount of time. Preferably, lens  62  is controlled by a DC voltage and presents a capacitive load; however, the lens  62  can be controlled by any suitable voltage and operate with any suitable electrical properties. 
     Lens  62  is electrically coupled to a power source  64  by electrically conductive line  66 ; however, lens  62  can be coupled to power source  64  in any suitable manner. Preferably, power source  64  is rechargeable through induction or other suitable means such as generating and storing electrical energy using eye and/or head movement to provide the energy to drive the generator; however, the power source  64  can be non-rechargeable, if desired. Similar to remote power source  54 , the power source  64  is preferably located in the posterior chamber  50 ; however, the power source  64  can be positioned outside the eye (e.g., under the scalp, within a sinus cavity, under the cheek, in the torso or in any other suitable location), within the sclera, between the sclera and the choroids or any other suitable location. Further, the power source  64  is preferably positioned such that it is not in the visual pathway. The power source  64  preferably includes a signal generator which can supply current to the lens  62  via electrically conductive line  66 ; however, the power source  64  can be without a signal generator, if desired, or can supply control signals to the lens  62  in any suitable manner. 
     Preferably, the power source  64  is coupled to a sensor  68  by electrically conductive line  70 ; however, the power source  64  can be coupled to sensor  68  in any suitable manner. The sensor  68  is preferably a tension sensor positioned on the zonules  20  so that the sensor  68  detects the amount of tension present in the zonules  20 ; however, the sensor  68  can be a wireless signal sensor, a neurotransmitter sensor, a chemical sensor, a pressure sensor or any other suitable sensor type and/or can be positioned in or near the ciliary muscle  22 , at or near the nerve controlling the ciliary muscle  22 , in the capsular bag  18  or in any other suitable location. Preferably, the sensor  68  detects the eye&#39;s attempt to cause its lens to accommodate; however, the sensor  68  can detect a manual attempt to accommodate the lens  62  (e.g., input through a wireless controller) or any other suitable input. The information detected at the sensor  68  is relayed to the power source  64  via line  70 , and the signal generator of the power source  64  generates a signal in accordance with the information. The signal is sent and passed through the lens  62 , which preferably changes shape as a result of the electrical current flowing through it; however, the lens  62  could change its index of refraction in response to the electrical current flowing through it or change its focal length in any other suitable manner. Preferably, line  70  includes two separate electrical pathways that electrically couple to lens  62  at different, preferably substantially opposite, locations so that one of the pathways can serve as a ground wire; however, the lens  62  can be grounded in any other suitable manner to enable current supplied via line  70  to flow through the lens  62 . As a result, similar to lens  38 , the eye&#39;s natural attempts to focus will result in accommodation of lens  62 . Response of lens  62  may vary from that of the natural lens; however, as with lens  38 , the neural systems which control the ciliary muscle  22  (and therefore the tension on the zonules  20 ), are provided with feedback from the optic nerve and visual neural pathways. As a result, the neural system can learn and adjust to the characteristics of the lens  62 . 
     The process of accommodation in response to electrical signals in accordance with one embodiment is shown in  FIG. 9 . At step  900 , the eye attempts to refocus at a different distance, and thus changes the tension on the zonules. At step  910 , a tension sensor detects the new tension level and relays the information to a control unit. The control unit preferably includes a power source; however, the control unit can include any suitable devices. At step  920 , the control unit determines the correct adjustment to be made to the current being passed through the lens in response to the tension sensor information. At step  930 , the control unit adjusts the current being passed through the lens and the process repeats at step  900 . 
     In another embodiment, as illustrated in  FIGS. 10-11 , the present invention can be used in an external lens. For example, the lens can be configured to be used with spectacles ( FIG. 10 ) or as a contact lens  FIG. 11 ). The embodiments of  FIG. 10-11  are configured to correct refractive errors in the eye. For example, the present embodiments can correct at least myopia, hyperopia and astigmatism. Furthermore, since these embodiments (as discussed in more detail below) can have their refractive properties altered, they are multi-focal lenses. Thus, these lenses can correct, among other disorders, presbyopia, or any combination of disorders. 
     When configured to be used in conjunction with spectacles  1000 , lens  1002  is preferably coupled to a frame  1004  that positions the lens  1002  relative to the cornea  1006  of the eye in any suitable manner. As with previous embodiments, the lens  1002  has a chamber or area  1008  (or multiple chambers or areas, if desired) that is configured to hold a fluid or a mixture of fluids or any other suitable substance. Chamber  1008  preferably includes two immiscible (i.e., non-mixing) fluids of different refractive index (or other suitable optical property); however, the chamber  1008  is not required to include two immiscible fluids of different refractive index. Preferably, one of the immiscible fluids is an electrically conducting aqueous solution and the other an electrically non-conducting oil, contained in a short tube with transparent end caps, as described above; however, the immiscible fluids can be any suitable fluids and can be contained in any suitable container. The above description of the fluids is applicable to the present invention. 
     Preferably, as with the embodiments above, the shape of the lens  1002  can be adjusted by applying an electric field across the hydrophobic coating such that it becomes less hydrophobic (a process called “electrowetting” that results from an electrically induced change in surface-tension); however, the shape of the lens  1002  can be adjusted by applying an electric field across any suitable portion of the lens  1002 . Preferably, as a result of this change in surface-tension, the aqueous solution begins to wet the sidewalls of the tube, altering the radius of curvature of the meniscus between the two fluids and hence the focal length of the lens. Increasing the applied electric field can preferably cause the surface of the initially convex lens to become less convex, substantially flat or concave; however increasing the applied electric field can cause the surface of the lens to change in any suitable manner. Preferably, decreasing the applied electric field has the opposite effect, enabling the lens  1002  to transition smoothly from being convergent to divergent, or vice versa, and back again repeatably. Thus, allowing the lens  1002  to repeatably focus on near and/or far objects. 
     The focal range of the lens  1002  can be any suitable range and can extend to infinity. Further, switching over the full focal range can occur in less than 10 ms or any other suitable amount of time. Preferably, lens  1002  is controlled by a DC voltage and presents a capacitive load; however, the lens  1002  can be controlled by any suitable voltage and operate with any suitable electrical properties. 
     Lens  1002  is electrically coupled to a power source  1010  by electrically conductive line  1012 ; however, lens  1002  can be coupled to power source  1010  in any suitable manner. Preferably, power source  1010  is rechargeable through direct electrical current, induction or other suitable means such as generating and storing electrical energy using eye and/or head movement to provide the energy to drive the generator; however, the power source  1010  can be non-rechargeable, if desired. Power source  1010  is preferably located on the frame  1004  of spectacles  1000 ; however, the power source  1010  can be positioned in any suitable location. The power source  1010  preferably includes a signal generator which can supply current to the lens  1002  via electrically conductive line  1112 ; however, the power source  1010  can be without a signal generator, if desired, or can supply control signals to the lens  1002  in any suitable manner. 
     Preferably, the power source  1010  is coupled to a sensor  1114  by electrically conductive line  1116 ; however, the power source  1010  can be coupled to sensor  1116  in any suitable manner (e.g. wirelessly). The sensor  1114  is preferably a distance sensor positioned on the front  1118  of frame  1004  so that the sensor  1114  detects the distance of an object away from the eye (such as a laser range finder); however, the sensor  1114  can be any suitable sensor type. Preferably, the sensor  1114  is positioned relative to the eye such that it detects the distance a specific object is from the eye and adjusts the lens  1002  accordingly; however, the sensor  1114  can detect a manual attempt to adjust the lens  1002  (e.g., input through a wireless controller or direct push buttons) or any other suitable input. The information detected at the sensor  1114  is relayed to the power source  1010  via line  1116 , and the signal generator of the power source  1010  generates a signal in accordance with the information. The signal is sent and passed through the lens  1002 , which preferably changes shape as a result of the electrical current flowing through it; however, the lens  1002  could change its index of refraction in response to the electrical current flowing through it or change its focal length in any other suitable manner. Preferably, line  1116  includes two separate electrical pathways that electrically couple to lens  1102  at different, preferably substantially opposite, locations so that one of the pathways can serve as a ground wire; however, the lens  1002  can be grounded in any other suitable manner to enable current supplied via line  1116  to flow through the lens  1002 . 
     Additionally, the lens  1002  can be wirelessly coupled to a sensor, such as sensor  64 , described above and adjust based on signals from the cilliary muscles and/or the zonules. Response of lens  1002  may vary from that of the natural lens; however, as with lenses described above, the neural systems which control the ciliary muscle  22  (and therefore the tension on the zonules  20 ), are provided with feedback from the optic nerve and visual neural pathways. As a result, the neural system can learn and adjust to the characteristics of the lens  1002 . 
       FIG. 11  illustrates another embodiment of the present invention, where the lens  1102  is a contact lens that is positioned on the external surface  1104  of the cornea  1105 . 
     As with lens  1002 , lens  1102  includes a chamber or area  1106  (or multiple chambers or areas, if desired) having a fluid  1108  therein. Preferably, fluid  1108  is the same as the fluid described above for lens  1002  and operates in the substantially the same manner; however, any suitable fluid and/or substance or combination thereof can be used. 
     As described above, lens  1102  is coupled to a power source  1110  via an electrical wire  1112 , or by any other suitable means. The power source  1110  is coupled to lens  1102  in any suitable manner (e.g., attached to a protrusion  1111 ). Power source  1110  and electrical wire  1112  are configured and operate in substantially the same manner as described above for lens  1002 . Any description of lens  1002  and power source  1010  is applicable to lens  1102  and power source  1110 . 
     Furthermore, lens  1102  can have a distance sensor (or any other sensor) that is located outside the eye and wirelessly coupled or directly wired to power source  1110 , as described above. The sensor can be a sensor coupled to the lens  1102  (or any other suitable place on or adjacent the eye) or it can be located in the eye, and operate in substantially the same manner as sensors described above. 
     Additionally, both lens  1002  and  1102  can have their respective refractive properties altered in any manner described herein and are not limited the specific descriptions above. For example, lens  1102  and lens  1002  can have their respective refractive properties altered by changing the fluidic pressure as described above. 
     As shown in  FIGS. 12 and 13 , one embodiment of the automated system of the present invention comprises flexible membrane, similar to the embodiments, described above, attached to a solid chamber where the membrane&#39;s surface can be made to act as a positive or negative surface by altering the fluid pressure inside the chamber. 
     The membrane can be constructed from any transparent elastomeric material. Depending on the membrane&#39;s peripheral attachment (e.g. circular) the membrane acts as a spherical (plus or minus 35.00 D) lens or (plus or minus 8.00 D) cylindrical lens when its attachment is rectangular ( FIGS. 12A ,  12 B and  13 ). 
     By combining one spherical and two cylindrical lens-membranes, positioned 45 degrees to one another, one can correct all low order aberration of the refractive errors. 
     Using a non-uniform thickness membrane or an additional lens module one can also correct the higher order aberrations of refractive errors and creation of an achromatic lens. The flexible membrane lens is adjusted to null the wavefront error of the eye. 
     When this system is combined with a relay telescope, the image of the eye pupil can be projected onto a wavefront sensor via a diachroic mirror to analyze the shape of the wavefront ( FIG. 13 ) while the person sees a near or distant object. The present system eliminates deformable mirrors and scanning parts; therefore it is a compact and stable unit. 
     The sensor in return corrects automatically all refractive errors of an eye by adding or subtracting fluid from the chamber holding the flexible membrane, thereby adjusting the curvature of the flexible membranes. 
     The final information is equal to the eye&#39;s refractive power of an eye for any given distance. Because of its simple design and light weight of the system both eyes of a person can be corrected simultaneously. 
     Additional application of this concept beside vision correction and photography includes microscope lenses, operating microscope, a lensometer capable of measuring accurately various focal points (power) of a multifocal lens or a multifocal diffractive lens, liquid crystal lenses etc. known in the art. A combination of the plus and minus flexible membrane lenses can also provide a lightweight telescope. Others include hybrid combination of this technology with diffractive, refractive and liquid crystal lenses. 
     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.