Patent Abstract:
A process of dry polishing molded or lathe cut intraocular lenses or like medical devices to removing flash, sharp edges and/or surface irregularities therefrom. The process includes gas and/or rotational tumbling of the intraocular lenses or like medical devices in a dry polishing media. The process is suitable for single piece and multipiece intraocular lenses of varying composition.

Full Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to methods of polishing intraocular lenses. More specifically, the present invention relates to methods of dry polishing intraocular lenses in a fluidized bed of particles to remove flash, surface irregularities and/or sharp edges from molded or lathe cut surfaces thereof.  
         BACKGROUND OF THE INVENTION  
         [0002]    Methods of molding articles from moldable materials have been known for some time. A common problem associated with molding techniques is the formation of excess material or flash on the edges of the molded article. Depending on the type of article formed in the molding process and the manner in which the article is used, the presence of excess material or flash can be undesirable. The same is also true of rough, irregular or sharp edges found on articles produced through a lathing process.  
           [0003]    Many medical devices, such as for example intraocular lens implants, require highly polished surfaces free of sharp edges or surface irregularities. In the case of intraocular lenses (IOLs), the lens is in direct contact with delicate eye tissues. Any rough or non-smooth surface on an IOL may cause irritation or abrading of tissue or other similar trauma to the eye. It has been found that even small irregularities can cause irritation to delicate eye tissues.  
           [0004]    Various methods of polishing are known in the art. U.S. Pat. Nos. 2,084,427 and 2,387,034 disclose methods of making plastic articles such as buttons that include tumbling the articles to remove projections of excess material or flash.  
           [0005]    U.S. Pat. No. 2,380,653 discloses a cold temperature tumbling process to remove flash from a molded article. This method requires the article to be tumbled in a rotatable container of dry ice and small objects such as wooden pegs. The cold temperature resulting from the dry ice renders the flash material relatively brittle, such that the flash is more easily broken from the article during the tumbling process.  
           [0006]    U.S. Pat. No. 3,030,746 discloses a grinding and polishing method for optical glass, including glass lenses. The method includes tumbling the glass articles in a composition of liquid, abrasive and small pellets or media. The liquid is disclosed as being water, glycerins, kerosene, light mineral oil and other organic liquids either alone or in combination. The abrasive component is described as being garnet, corundum, boron carbide, cortz, aluminum oxide, emery or silicon carbide. The media is disclosed as being ceramic cones, plastic slugs, plastic molding, powder, limestone, synthetic aluminum oxide chips, maple shoe pegs, soft steel diagonals, felt, leather, corn cobs, cork or waxes.  
           [0007]    U.S. Pat. No. 4,485,061 discloses a method of processing plastic filaments which includes abrasive tumbling to remove excess material.  
           [0008]    U.S. Pat. Nos. 4,541,206 and 4,580,371 disclose a lens holder or fixture used for holding a lens in a process of rounding the edge thereof. The process includes an abrasive tumbling step.  
           [0009]    U.S. Pat. No. 5,133,159 discloses a method of tumble polishing silicone articles in a receptacle charged with a mixture of non-abrasive polishing beads and a solvent which is agitated to remove surface irregularities from the articles.  
           [0010]    U.S. Pat. No. 5,571,558 discloses a tumbling process for removing flash from a molded IOL by applying a layer of aluminum oxide on a plurality of beads, placing the coated beads, alcohol, water and silicone IOLs in a container and tumbling the same to remove flash.  
           [0011]    U.S. Pat. No. 5,725,811 discloses a process for removing flash from molded IOLs including tumbling the IOLs in a tumbling media of 0.5 mm diameter glass beads and 1.0 mm diameter glass beads, alcohol and water.  
           [0012]    Prior methods of removing flash or surface irregularities, such as described above, may be inadequate or impractical in the manufacture of certain types of IOLs. For example, certain IOLs formed from relatively soft, highly flexible material, such as silicone, are susceptible to chemical and/or physical changes when subjected to cold temperatures. For this reason, certain types of cryo-tumbling or cold temperature tumbling may be impractical in the manufacture of IOLs made from such materials. Additionally, certain types of abrasive tumbling processes may be suitable for harder lens material, such as glass or polymethylmethacrylate (PMMA), but may not be suitable for softer lens materials. Also, most tumbling processes known in the art require the lens to be submersed in a liquid that may not be suitable for some lens materials or manufacturing processes. Accordingly, a need exists for a suitable process for removing flash and/or irregularities from molded or lathe cut IOLs made of various materials.  
         SUMMARY OF THE INVENTION  
         [0013]    The present invention relates to methods for dry polishing IOLs. IOLs are currently either molded in removable molds or lathe cut. Subsequent to these operations, the IOLs have surface roughness or sharp edges that need to be minimized or eliminated. After polishing methods such as tumbling the IOLs in a container with glass beads and a liquid, the IOLs must be dried or in the case of hydrogels dehydrated, prior to further processing. Drying or dehydrating the IOLs can be both expensive and time consuming. The dry polishing methods of the present invention eliminate the need for drying or dehydrating IOLs. This is particularly important in the case of surface coated IOLs where a coating or surface treatment can not be consistently applied in the presence of moisture.  
           [0014]    The first method of dry polishing IOLs in accordance with the present invention consists of obtaining a polishing chamber having two opposed open ends, placing glass-spun wool in each open end and polishing material and IOLs in the center. Air, or any other inert gas or gases, is then passed into one end of the polishing chamber and out of the other end while the length of the polishing chamber is preferably maintained in a vertical position. The flow of air keeps the IOLs and polishing material buoyant resulting in dry polished IOLs. After polishing the IOLs, the IOLs are removed from the polishing chamber and polishing material with the use of a sieve. The IOLs are then easily handled and surface treated at this stage without having to dry the same.  
           [0015]    The second and third methods of dry polishing IOLs in accordance with the present invention consist of obtaining an IOL container with one or more optic clamps or flexible optic loops extending from one or more but preferably one rigid arm members. One IOL is placed in each open hinged optic clamps or flexible optic loops of the IOL container so that the IOLs&#39; haptics extend from slots formed in the optic clamps or flexible optic loops. In the case of the optic clamps, once an IOL is positioned therein, the open hinge of the optic clamp is snapped close to secure the IOL in place. The optic clamps when closed only contact the outer peripheral edges of the IOLs positioned therein. Alternatively, the flexible optic loops are designed such that one IOL snaps or slips into position within each flexible optic loop thereof leaving all but the IOL optic peripheral edges exposed. The IOL container with IOLs positioned therein is then snapped into place within a polishing chamber using retention means formed therein. The polishing chamber and the axially concentric IOL tube are then preferably maintained in a horizontal position. The retention means inside the polishing chamber removably fixes the IOL container within the polishing chamber to prevent rotation of the IOL container within the polishing chamber. A dry polishing medium is placed inside the polishing chamber and the one or more open ends thereof removably sealed. The polishing chamber is then axially rotated. As the polishing chamber is rotated, the polishing medium repeatedly contacts the exposed IOL surfaces thus polishing the same. The duration of tumbling and the revolutions per minute of the polishing chamber can be adjusted to achieve the desired degree of polishing. Since the slots of the IOL container protect the IOL optic peripheral edges, the IOL optic peripheral edges remain sharp while the remainder are polished. Following polishing, the IOLs are removed from the IOL container. The polished IOLs are then easily handled and surface treated without having to dehydrate or dry the same.  
           [0016]    The fourth method of dry polishing IOLs in accordance with the present invention involves placing IOLs and dry polishing medium within a polishing chamber so that the IOLs are evenly dispersed throughout. The polishing chamber is then removably sealed and placed on a tumbler and tumbled at a specified speed for a specified period of time. As the polishing chamber tumbles, the dry polishing medium repeatedly contacts the IOL surfaces thereby polishing the same.  
           [0017]    Accordingly, it is an object of the present invention to provide a method for dry polishing lathe cut IOLs.  
           [0018]    Another object of the present invention is to provide a method for dry polishing molded IOLs.  
           [0019]    Another object of the present invention is to provide a method for polishing IOLs without the use of liquids.  
           [0020]    Another object of the present invention is to provide a method for polishing IOLs that eliminates the need to dry or dehydrate the same prior to further processing.  
           [0021]    Another object of the present invention is to provide a method for dry polishing IOLs that is suitable for a variety of IOL materials.  
           [0022]    Still another object of the present invention is to provide a method for polishing IOLs that allows for consistent surface coating without additional process steps.  
           [0023]    These and other objectives and advantages of the present invention, some of which are specifically described and others that are not, will become apparent from the detailed description, drawings and claims that follow, wherein like features are designated by like numerals. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    [0024]FIG. 1 is a plan view of an intraocular lens with open haptics;  
         [0025]    [0025]FIG. 2 is a plan view of an intraocular lens with looped haptics;  
         [0026]    [0026]FIG. 3 is a plan view of a polishing chamber of the present invention;  
         [0027]    [0027]FIG. 4 is a plan view of the polishing chamber of FIG. 3 connected to an air source;  
         [0028]    [0028]FIG. 5 is a plan view of the polishing chamber of FIG. 4 after loading;  
         [0029]    [0029]FIG. 6 is a perspective view of the IOL container of the present invention;  
         [0030]    [0030]FIG. 7 is a perspective view of the IOL container of FIG. 6 with IOLs loaded therein;  
         [0031]    [0031]FIG. 8 is a plan view of the polishing chamber of FIG. 3 with the IOL container of FIG. 7 removably fixed therein;  
         [0032]    [0032]FIG. 9 is a perspective view of a second embodiment of the IOL container of the present invention;  
         [0033]    [0033]FIG. 10 is a perspective view of the IOL container of FIG. 9 with IOLs loaded therein; and  
         [0034]    [0034]FIG. 11 is a plan view of the polishing chamber of FIG. 3 with the IOL container of FIG. 10 removably fixed therein. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]    [0035]FIGS. 1 and 2 illustrate typical intraocular lenses (IOLs)  10  produced using dry polishing methods of the present invention. Each IOL  10  typically has an optic portion  12  defined by an outer peripheral edge  18  and one or more but typically two to four haptics  14  of either an open configuration  21  as illustrated in FIG. 1 or a looped configuration  23  as illustrated in FIG. 2. The haptics  14  are integrally formed on outer peripheral edge  18  or permanently attached thereto through processes such as heat, physical staking and/or chemical bonding. The typical IOL  10  may be made from a variety of materials such as but not limited to polymethylmethacrylate (PMMA), silicones, hydrophilic acrylics, hydrophobic acrylics or combinations thereof.  
         [0036]    [0036]FIG. 3 illustrates a polishing chamber  20 , which may be made of any suitable material such as but not limited to glass, plastic, metal or a combination thereof but preferably, glass for visibility and cleaning ease. Polishing chamber  20  may be of any geometric configuration defining an interior area  28  and having one or more depending on the polishing method selected, but preferably two openings  22  and  24  therein for ease in cleaning the same. Preferably, polishing chamber  20  is of a tubular configuration defined by a tubular body  26  having two opposed open ends  22  and  24 . Tubular body  26  may optionally decrease in diameter abruptly to form partial end walls  25  at one or both open ends  22  and/or  24  for increased structural integrity. Open end  22  is defined by an extended rim  44 . As illustrated in FIG. 4, extended rim  44  is suitable for removable attachment, by various methods known to those skilled in the art, to end  41  of tubing  40 . Suitable methods of attachment include but are not limited to friction fit, male and female threaded means, snap fit interlocking means and tab and groove interlocking means whereby snap fit interlocking means is preferred for ease of assembly and strength of the removable attachment. Optionally, a perforated cap or frit  46  may be snap fit onto extended rim  44  prior to attachment of end  41  of tubing  40 . Removably attached to opposed end  43  of tubing  40  by attachment methods such as those discussed above, but preferably by snap fit interlocking means, is a gas source  38  of air or any other inert gas or gases. After attaching gas source  38  to polishing chamber  20  using tubing  40 , a retaining material  34  is placed in interior area  28  at open end  22  as best illustrated in FIG. 5. Suitable retaining material  34  includes but is not limited to glass-spun wool, cotton, wool, and other natural or synthetic fiber materials of like density, but preferably glass-spun wool to avoid air borne fiber contamination within the manufacturing facility. After placing retaining material  34  in interior area  28 , polishing media  36  and IOLs  10  are loaded within interior area  28 . Suitable polishing media  36  includes but is not limited to glass beads, silica gel, silica and aluminum oxide whereby silicone and aluminum oxide is preferred due to ready availability at low cost. After the polishing media  36  and IOLs  10  are placed within polishing chamber  20 , retaining material  34  is placed in interior area  28  to fill the same at open end  24 . A perforated cap or frit  46  is then removably attached in accordance with methods discussed above to extended rim  48  of open end  24 . It is preferred that frit  46  is removably attached by snap fit interlocking means to extended rim  48  for ease of use. Once assembled as described, the length of polishing chamber  20  is preferably vertically positioned and gas source  38  is activated to provide a flow of one or more inert gases such as for example but not limited to air through polishing chamber  20  to polish IOLs  10  placed therein. Preferably the one or more inert gases are forced through said polishing chamber at a rate of approximately 1 to 6 cubic feet per minute. After an adequate amount of time to polish IOLs  10 , preferably approximately 2 to 60 hours but most preferably approximately 12 to 48 hours, frit  46  is removed from extended rim  48  and retaining material  34  is removed from interior area  28 . Polishing media  36  and IOLs  10  may then be poured from polishing chamber  20  into an appropriately sized sieve to separate the polished IOLs  10  from polishing media  36 .  
         [0037]    Another method of dry polishing IOLs  10  in accordance with the present invention to produce more defined peripheral edges  18  on optic portion  12  is likewise provided. More defined outer peripheral edges  18  are desirable to reduce or prevent posterior capsular opacification of IOLs  10  after implantation thereof within an eye. The subject dry polishing method utilizes an IOL container  50  as illustrated in FIGS. 6 and 7. IOL container  50  may be made of any suitable material such as but not limited to glass, plastic, natural or synthetic rubber, metal or a combination thereof but preferably a combination of glass or rigid plastic and flexible plastic or rubber for function and durability. IOL container  50  is preferably of an elongated shape with one or more but preferably numerous flexible optic loops  51 . Preferably IOL container  50  is formed by one or more but preferably one rigid arm member  88  with numerous flexible optic loops formed therewith or attached thereto. Flexible optic loops  51  are formed with slots  52  to accommodate any number of haptics  14  on IOL  10 . IOLs  10  are removably positioned and maintained by friction within flexible optic loops  51  as illustrated in FIG. 7. Haptics  14  of IOLs  10  extend from slots  52  in flexible optic loops  51  to allow polishing of the same. IOL container  50  may be fixed within polishing chamber  20  as illustrated in FIG. 8 by snapping rigid arm member  88  within retaining means  86 . In accordance with this particular method, polishing chamber  20  may optionally have only one open end  22  rather than two open ends  22  and  24 . If polishing chamber  20  has two open ends  22  and  24 , one open end  22  is removably or permanently sealed by means discussed above with a cap  84 . Interior area  28  is then loaded through open end  24  with polishing media  36 . Suitable polishing media  36  includes but is not limited to glass beads, silica gel, silica and aluminum oxide whereby silicone and aluminum oxide is preferred due to ready availability at low cost. After filling polishing chamber  20  with polishing media  36 , the second open end  24  is removably sealed by means discussed above with a cap  84 . If polishing chamber  20  has only one open end  22 , interior area  28  is loaded through open end  22  with polishing media  36 . After filling polishing chamber  20  with polishing media  36 , open end  22  is removably sealed by means discussed above with a cap  84 . Polishing chamber  20  once filled with IOL container  50  and polishing media  36 , is placed on a tumbler (not shown) to axially rotate the same as described in U.S. Pat. Nos. 5,571,558, 5,649,988 and 5,725,811 each incorporated herein in its entirety by reference. After allowing polishing chamber  20  to rotate at a specified speed, preferably 50 to 200 revolutions per minute but most preferably 100 revolutions per minute, and for a specified period of time, preferably 2 to 48 hours but most preferably 8 to 36 hours, polishing chamber  20  is removed from the tumbler. The tumbler speed and the duration of the tumbling will vary depending upon the material of IOL  10 , the polishing media  36  selected and the degree of smoothness desired. A cap  84  is removed from polishing chamber  20  and polishing media  36  is removed therefrom. IOL container  50  may then be removed from polishing chamber  20  and polished IOLs  10  removed from flexible optic loops  51 .  
         [0038]    Another method of dry polishing IOLs  10  in accordance with the present invention to produce more defined outer peripheral edges  18  on optic portion  12  in effort to reduce or prevent posterior capsular opacification of IOLs  10  after implantation within an eye utilizes an IOL container  80  as illustrated in FIGS. 9 and 10. IOL container  80  may be made of any suitable material such as but not limited to glass, plastic, natural or synthetic rubber, metal or a combination thereof but preferably a combination of glass or rigid plastic and flexible plastic or rubber for function and durability. IOL container  80  may be formed in any configuration that allows the haptics  14  and optic portions  12  of IOLs  10  to be exposed while protecting outer peripheral edge  18  from polishing. Preferably IOL container  80  is of an elongated form defined by one or more but preferably one rigid arm member  88 . Rigid arm member  88  is equipped with one or more but preferably numerous optic clamps  90 . Slots  92  are formed in optic clamps  90  to allow haptics  14  to extend through beyond the exterior  94  of optic clamps  90  when an IOL  10  is positioned within the interior  96  thereof. In order to allow for IOL  10  to be positioned within interior  96 , each optic clamp  90  has a hinge  98 , a tab  100  and a groove  102  for opening and securely closing optic clamp  90 . To place IOL  10  within interior  96 , optic clamp  90  is opened by removing tab  100  from groove  102  and thus opening hinge  98 . IOL  10  is then positioned within the optic clamp  90  formed to specifically conform or match outer peripheral edge  18  with haptics  14  extending through slots  92 . Optic clamp  90  is then securely closed by inserting tab  100  into groove  102  for removable attachment by snap fit interlocking means, thus closing hinge  98 . IOL container  80  loaded with IOLs  10  is illustrated in FIG. 10. Haptics  14  of IOLs  10  extend from slots  92  in optic clamp  90  to allow polishing of the same. IOL container  80  may be fixed within polishing chamber  20  as illustrated in FIG. 11 by snapping rigid arm member  88  within retaining means  86 . In accordance with this particular method, polishing chamber  20  may optionally have only one open end  22  rather than two open ends  22  and  24 . If polishing chamber  20  has two open ends  22  and  24 , one open end  22  is removably or permanently sealed by means discussed above with a cap  84 . Interior area  28  is then loaded through open end  24  with polishing media  36 . Suitable polishing media  36  includes but is not limited to glass beads, silica gel, silica and aluminum oxide whereby silicone and aluminum oxide is preferred due to ready availability at low cost. After filling polishing chamber  20  with polishing media  36 , the second open end  24  is removably sealed by means discussed above with a cap  84 . If polishing chamber  20  has only one open end  22 , interior area  28  is loaded through open end  22  with polishing media  36 . After filling polishing chamber  20  with polishing media  36 , open end  22  is removably sealed by means discussed above with a cap  84 . Polishing chamber  20  once filled with IOL container  80  and polishing media  36 , is placed on a tumbler (not shown) to axially rotate the same as described above. After allowing polishing chamber  20  to rotate at a specified speed, preferably 50 to 200 revolutions per minute but most preferably 100 revolutions per minute, and for a specified period of time, preferably 2 to 48 hours but most preferably 8 to 36 hours, polishing chamber  20  is removed from the tumbler. The tumbler speed and the duration of the tumbling will vary depending upon the material of IOL  10 , the polishing media  36  selected and the degree of smoothness desired. A cap  84  is removed from polishing chamber  20  and polishing media  36  is removed therefrom. IOL container  80  may then be removed from polishing chamber  20  and polished IOLs  10  removed from optic clamp  90 .  
         [0039]    Another method for dry polishing IOLs  10  in accordance with the present invention uses polishing chamber  20 . In this particular method, polishing chamber  20  may optionally have only one open end  22  rather than two open ends  22  and  24 . If polishing chamber  20  has two open ends  22  and  24 , one open end  22  is removably or permanently sealed by means discussed above with a cap  84 . Interior area  28  is then loaded through open end  24  with IOLs  10  and polishing media  36 . Suitable polishing media  36  includes but is not limited to glass beads, silica gel, silica and aluminum oxide whereby silicone and aluminum oxide is preferred due to ready availability at low cost. After filling polishing chamber  20  with IOLs  10  and polishing media  36 , the second open end  24  is removably sealed by means discussed above with a cap  84 . If polishing chamber  20  has only one open end  22 , interior area  28  is loaded through open end  22  with IOLs  10  and polishing media  36 . After filling polishing chamber  20  with IOLs  10  and polishing media  36 , open end  22  is removably sealed by means discussed above with a cap  84 . Polishing chamber  20  once filled is placed on a tumbler (not shown) to axially rotate the same as described above. After allowing polishing chamber  20  to rotate at a specified speed, preferably 50 to 200 revolutions per minute but most preferably 100 revolutions per minute, and for a specified period of time, preferably 2 to 48 hours but most preferably 8 to 36 hours, polishing chamber  20  is removed from the tumbler. The tumbler speed and the duration of the tumbling will vary depending upon the material of IOL  10 , the polishing media  36  selected and the degree of smoothness desired. Cap  84  is removed from polishing chamber  20  and IOLs  10  and polishing media  36  are removed from polishing chamber  20 . IOLs  10  are separated from polishing media  36  using an appropriately sized sieve.  
         [0040]    The methods for dry polishing IOLs of the present invention are described in still greater detail in the Examples that follow.  
       EXAMPLE 1  
       [0041]    Dry Polishing of Silicone and Hydroview™ Intraocular Lenses  
         [0042]    Ten silicone intraocular lenses and ten Hydroview intraocular lenses were obtained for dry polishing in accordance with the present invention. Hydroview lenses are bicomposite lenses having a hydrogel optic portion and polymethylmethacrylate haptics. Two glass polishing chambers tubular in form having a 2-inch internal diameter and 6 inches in length were obtained. One open end of one of the polishing chambers was capped with a plastic perforated cap or frit and the chamber was loaded with a glass spun wool plug in contact with the frit. Ten Hydroview lenses were then interspersed throughout approximately 20 gm of glass beads of 0.4 mm or less diameter and loaded onto the glass spun wool plug within the polishing chamber. Another glass spun wool plug was used to fill the remainder of the polishing chamber interior space prior to using a frit to cap the second polishing chamber opening. An air source was connected to the one of the frits using plastic tubing and a clamp and air flow was activated. The airflow was maintained at approximately 2 cubic feet per minute for approximately 48 hours. An air flow rate through the polishing chamber should be maintained at a level adequate to keep the IOLs buoyant and should be maintained for a period of time sufficient to achieve the desired level of IOL smoothness. IOL polishing occurs as the glass beads churned by the airflow bombard the IOLs. Additionally, one open end of the other polishing chamber was capped with a plastic perforated cap or frit and the chamber was loaded with a glass spun wool plug in contact with the frit. Ten silicone lenses were then interspersed throughout approximately 20 gm of glass beads of 0.4 mm or less diameter and loaded onto the glass spun wool plug within the polishing chamber. Another glass spun wool plug was used to fill the remainder of the polishing chamber interior space prior to using a frit to cap the second polishing chamber opening. An air source was connected to the one of the frits using plastic tubing and a clamp and airflow was activated. The airflow was maintained at approximately 4 cubic feet per minute for approximately 24 hours. An air flow rate through the polishing chamber should be maintained at a level adequate to keep the IOLs buoyant and should be maintained for a period of time sufficient to achieve the desired level of IOL smoothness. IOL polishing the glass beads churned by the airflow bombard the IOLs. The results Ls so produced are set forth in Chart A-1&amp;2 below.  
         [0043]    IOLs—Dry Polish  
                                                                                                                   control RMS   2 days polished RMS   4 days polished           roughness   roughness   RMS roughness                optical   haptic   optical   haptic   optical   haptic                        1   10.256   4.385   29.447   7.894   25.53   7.41       2   13.603   3.991   35.53   9.63    26.379   7.139       3   9.021   9.228   30.169   5.965   23.953   9.95       4   14.169   5.169   31.406   6.011   34.543   38.136       5   11.361   6.69   27.94   8.433   31.79   51.588       6   14.647   6.679   33.41   6.04    33.549   6.396       7   9.42   10.265   27.376   11.401    30.185   45.595       8   9.591   11.48   29.938   —   30.902   40.866       9   9.844   9.404   27.504   —   29.084   52.389       Average   11.3   7.5   30.3   7.9   29.5   28.8       s.d.   2.2   2.7   2.8   2.1   3.6   20.5                  
 
         [0044]    [0044]                     
       EXAMPLE 2  
       [0045]    Dry Polishing of Hydroview Intraocular Lenses  
         [0046]    Twenty Hydroview intraocular lenses were obtained in accordance with the present invention. About 500 g of the polishing medium, a mixture of 0.5 mm and 0.1 mm glass beads, was placed in a clear glass bottle with a screw cap. The IOLs were loaded into the bottle with the polishing medium. The bottle was tightly capped and placed horizontally on a tumbler. The tumbler was set at 100 revolutions per minute for 36 hours. The IOLs were samples at the end of 2 hours, 4 hours, 8 hours, 12 hours, 16 hours and 32 hours. The sampled IOLs were analyzed for optic peripheral edge sharpness, haptic polishing and optic zone polishing using high magnification microscopes. The results are set forth below in Charts B-1 and B-2, and Chart C, wherein the 8-hour samples show that the desired polishing can be achieved while maintaining reasonable sharpness on the optic peripheral edges. 
         
         
         
 
         [0047]    The methods of dry polishing IOLs as well as the IOLs produced thereby in accordance with the present invention provide a cost effective means by which multiple IOLs may be simultaneously polished without having to dry or dehydrate the same prior to further processing steps such as applying a consistent surface coating. Additionally, the methods of dry polishing IOLs of the present invention allows the manufacturer to polish an IOL&#39;s haptics while maintaining well defined edges on the optic portion thereof. This is and important feature to eliminate future posterior capsular opacification of the IOL after implantation.  
         [0048]    While there is shown and described herein certain specific methods using specific equipment of the present invention, it will be manifest to those skilled in the art that various modifications may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.

Technology Classification (CPC): 1