Abstract:
A device and method of use thereof for incrementally adjusting the size and/or shape of a particular body part is provided. The device comprises first and second layers each formed of a synthetic resin. The first layer is formed of a heat-shrinkable material having a low melting point while the second layer has a melting point much higher than the first layer. Upon being subjected to energy, the first layer will shrink or contract causing the second layer, and thus the overall device, to bend in the direction of contraction. In use, the device is inserted into the particular body part after which energy is applied to the device so as to cause the body to expand, move, reshape, etc. The invention is particularly useful for treatment of accommodative disorders of the eye by positioning one or more of the devices within the eye sclera or attached to the sclera around the limbus so that the device bends and causes the size and shape of the sclera to be altered, restoring normal ocular functions such as accommodation or intraocular pressure.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is broadly concerned with a device which can be implanted in a body part (e.g., eye, tissue, artery) and methods of externally manipulating the device to adjust or alter the configuration of the body part. More specifically, the invention is directed towards the use of that device to adjust the curvature of the sclera of the eye so as to alter functional ocular structural relationships (e.g., such as to restore the accommodative ability of the eye), thus treating various eye conditions. 
   2. Description of the Prior Art 
   In order for the eye to clearly see an object at a distance of about twenty feet or greater, the object must be focused on the retina of the eye. When this occurs in the relaxed state of the eye, it is referred to as “emmetropia.” If the focal point is anterior to the retina, it is classified as “myopic.” On the other hand, if the focal point is behind the retina, it is classified as “hyperopic.” 
   Refractive correction is required to correct these focusing errors. This has typically been accomplished by the natural lens or by medical or surgical refractive devices. However, after the eye has been made to correctly focus on an object at a distance, it must then be capable of changing its refractive ability to see an object as it comes nearer the eye. This is accomplished physiologically through changes in the natural lens referred to as accommodation. 
   The ocular structures involved in accommodation include filaments inserted onto the lens equator and called zonules or zonular fibers. The zonules are connected to the ciliary body which is a muscle attached to the sclera that encircles and thus, in cooperation with the zonules, suspends the eye&#39;s lens. The actual mechanism by which these structures influence accommodation is still highly debated, but includes changes in lens shape and position with subsequent change in the overall refractive power of the eye. 
   Loss of accommodative ability, or presbyopia, occurs naturally with aging. It becomes noticeable at about forty years of age, and consistently worsens until about seventy years of age, at which time accommodation is effectively nonexistent. Theories concerning the causes of the loss of accommodative ability include increasing rigidity of the lens or its capsule, lens enlargement, laxity of the zonules, aging of the ciliary body, and combinations of the foregoing. 
   The usual way to correct this problem is to use bifocal lenses. However, some people dislike wearing glasses, particularly bifocals, for various reasons. One problem with bifocal lenses is that they present lines where the two portions of the lens are joined together. Furthermore, people must become accustomed to reading through one relatively small portion of the lens, while looking at distant objects through a different portion of the lens. Bifocal glasses also have the same disadvantages present in regular glasses. Such disadvantages include the fact that the glasses are breakable, become fogged when coming in from the cold, steam up in hot weather, and require frequent cleaning. 
   Other treatments have been attempted to correct presbyopia. For example, U.S. Pat. Nos. 5,928,129 and 5,802,923 each disclose the production of “bifocal-like” refractive correction through laser ablation of the inferior cornea. 
   Treatment methods have attempted to return the accommodative ability to a presbyope via expansion of the scleral radius in the vicinity of the ciliary body by a scleral expansion band (U.S. Pat. No. 5,489,299) or by a band which is adjustable at the time of placement (U.S. Pat. No. 5,354,331). Some methods have even shortened the zonules connecting the ciliary body to the lens by enzymes, heat, radiation, or surgical repositioning of the ciliary body. 
   Adjustable, ocular refractive devices for use in the cornea have been developed as well. Such adjustable devices include those which are adjustable at the time of placement. For example, U.S. Pat. No. 5,681,869 describes a poly(ethylene oxide) gel that is injected into the cornea in an amount sufficient to produce the required refractive correction. Additionally, U.S. Pat. No. 5,489,299 discloses a length-adjustable scleral expansion band for treatment of presbyopia, with the band length being measured and set at the time of placement. U.S. Pat. No. 5,919,228 discloses a corneal ring comprised of a memory metal that, upon insertion into the cornea, is caused to reach a temperature at which it assumes a prior impressed shape thus altering the shape of the cornea. 
   Other prior art devices include those which require further surgery to modify them if necessary after placement. For example, U.S. Pat. No. 5,855,604 discloses a hollow device placed into the cornea stroma. The device includes quantities of strands which may be removed at the time of placement, or which may be removed or added by surgery as needed after placement. 
   Each of the foregoing prior art techniques attempted thus far are lacking in that they only correct presbyopia at one particular stage of the disorder. Thus, as the condition worsens, the treatment would need to be repeated or otherwise enhanced. Or, in case of adjustable devices, additional surgery is needed to make the desired modifications. All of this poses undue risk to the eyes with each successive treatment. 
   SUMMARY OF THE INVENTION 
   The present invention overcomes the problems of the prior art by broadly providing a device and method of using the device which allows for a single surgical device implantation and successive, incremental adjustments of the device as necessary through externally applied energy. 
   In more detail, the inventive device comprises a first shrinking layer formed of a synthetic resin and a second bending layer formed of a synthetic resin and attached to said first layer. Optionally, a third barrier layer can be attached to the first shrinking layer to assist in dissipating the energy applied to the device. 
   Advantageously, the device is designed so that, upon the application of energy (e.g., laser energy) thereto, the first layer will shrink or contract as it melts, thus pulling the second layer to provide directional bending of the device. Because the second layer has a higher melting point (and often a lower melt index) than the first layer, it remains substantially free of shrinking during this process. 
   According to the inventive methods, the device is placed within a body part (e.g., an eye) whose size or shape is to be altered. Once the device is inserted, energy is applied (preferably externally) to the device causing it to bend as described above. As the device bends, it will cause the body part to likewise expand or move in the area surrounding the device. 
   After the application of energy to the device, measurements can be taken to determine whether sufficient expansion or movement has occurred, depending upon the desired treatment for which the inventive method is being utilized. If more expansion or movement is necessary, then additional energy can be applied to the device, and the measurements taken again. The foregoing steps can be repeated as many times as necessary until the desired result is obtained. Furthermore, the steps can be repeated long after the device has been inserted as further adjustments become necessary. The foregoing device and method is particularly useful for treating eye conditions such as presbyopia, hyperopia, glaucoma, and ocular hypertension. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view of an eye depicting the formation of scleral pockets during surgery according to the inventive methods; 
       FIG. 2  is an enlarged fragmentary view showing the insertion of the inventive device into a scleral pocket formed in  FIG. 1 ; 
       FIG. 3  is a plan view of the eye of  FIG. 1  with a device according to the invention implanted in each of the previously formed scleral pockets; 
       FIG. 4  is a cross-sectional view taken along line  4 - 4  of the eye of  FIG. 3 , depicting the cross-section of the inventive device and illustrating the application of energy to the device; and 
       FIG. 5  is a view similar to that of  FIG. 4 , depicting the change in curvature of the device and the sclera after the application of energy to the device. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Turning now to the figures, an eye  10  is depicted in  FIG. 1 . The eye  10  comprises a white, tough sclera  12  which encompasses most of the globe and a transparent cornea  14 , which constitutes the anterior segment of the outer coat. The circular junction of the cornea  14  and the sclera  12  forms a limbus  16 . External rectus muscles  18  control the movement of the eye  10 . 
   The remaining internal components of the eye are not shown in the accompanying figures, but are well known to those skilled in the art. Briefly, the eye  10  contains a natural crystalline lens enclosed in a thin, membranous capsule located immediately posterior to the iris  20 , suspended centrally posterior to the pupil  22  on the optical axis of the eye. The lens is suspended by zonules extending between the lens capsule (at the equator of the lens) and the ciliary body. The ciliary body lies just under the sclera  12  (i.e., just inwardly of the sclera) and is attached to the inner surface of sclera  12 . The foregoing internal workings of the human eye are described and illustrated in detail in U.S. Pat. No. 6,007,578, incorporated herein by reference. 
   According to the inventive process, a scalpel  26  is used to make incisions  24   a - d . The incisions  24   a - d  are made adjacent to the rectus muscle insertions  18  approximately over the region of the ciliary body. Scleral pockets  28   a - d  are then formed at this depth by advancing the scalpel  26  towards the next adjacent rectus muscle insertion  18 . At their nearest point, the respective inner edges  29   a - d  of the pockets  28   a - d  should be a distance of from about 0.5-3.5 mm, and preferably about 2 mm posterior to the limbus  16 . A device  30   a - d  according to the invention is then inserted into each respective pocket  28   a - d  (see  FIG. 2 ). Each of the incisions  24   a - d  are closed with sutures  52  (which may be “hidden” in the closed pockets) so that the devices  30   a - d  are completely enclosed within their respective pockets  28   a - d  and at least partially overlie the ciliary body. There is substantially no scleral radius expansion produced by the device at this point in the process. 
   Device  30   c  is shown in vertical cross-section in  FIGS. 4-5 . In more detail, the depicted device  30   c  is nontubular and comprises a low melting point, shrinking layer  34  and a high melting point, bending layer  36  posterior to shrinking layer  34 . Each of layers  34 ,  36  is moderately curved and abuts against the other so that the curvature of device  30  substantially corresponds to the curvature of the sclera  12 . Furthermore, in the embodiment shown, devices  30   a - d  include optional “notched” corners  33  which would allow for anchoring of the device with sutures either to the scleral surface or within the scleral pocket(s). 
   Shrinking layer  34  is preferably formed of a low melting point, non-toxic material which is heat-shrinkable. Thus, layer  34  should be formed of a material having a melting point of less than about 100° C., preferably from about 45-60° C., and more preferably from about 50-55° C. In some embodiment, layer  34  should be formed of a material having a melt index of at least about 4.5 g/10 min., preferably from about 6.3-26.0 g/10 min., and more preferably from about 6.3-15.0 g/10 min. (at an extrusion pressure of 2.16 kg and a temperature of 190° C. as defined by ASTM D-1238). A particularly preferred material for use as layer  34  is a polymethylmethacrylate (PMMA) or a mixture of polymethylmethacrylates wherein the polymethylmethacrylate or mixture thereof has the described melting point and/or melt index. A particularly preferred polymethmethacrylate for use as shrinking layer  34  is sold under the name ICI 924 CL (available from ICI Acrylics, Inc.). 
   Bending layer  36  is preferably formed of a high melting point, non-toxic material which is bendable, but will not readily shrink upon heat application. Thus, bending layer  36  should be formed of a material having a melting point of at least about 45° C., preferably from about 60-100° C., and more preferably from about 70-80° C. In some embodiments, layer  36  should be formed of a material having a melt index of less than about 4.4 g/10 min., preferably from about 1.1-4.4 g/10 min., and more preferably from about 1.1-2.2 g/10 min (at an extrusion pressure of 2.16 kg and a temperature of 190° C. as defined by ASTM D-1238). Similar to shrinking layer  34 , a particularly preferred material for use as bending layer  36  is a polymethylmethacrylate or a mixture of polymethylmethacrylates wherein the polymethylmethacrylate or mixture thereof has the described melting point and/or melt index. A particularly preferred polymethylmethacrylate for use as bending layer  36  is sold under the name ICI 1000 ECL (available from ICI Acrylics, Inc.). 
   In another embodiment, the ASTM D-1238 melt index of shrinking layer  34  is least about 2 times, preferably at least about 4 times, and more preferably from about 6-26 times greater than the ASTM D-1238 melt index of bending layer  36 . In another embodiment, the melting point of bending layer  36  is at least about 5° C., preferably at least about 10° C., and more preferably from about 20-30° C. greater than the melting point of shrinking layer  34 . 
   Other types of materials (both synthetic and natural resins as well as plastics formed from these resins) can be utilized to form shrinking layer  34  or bending layer  36 . Other suitable synthetic resins include polyethylene, polypropylene, polyvinyl chloride, and polytetrafluorine. It may also be desirable to incorporate certain agents into the layers, depending upon the application. Such agents include physiologically acceptable metals (e.g., titanium, gold, platinum, tantalum, stainless steel), ceramics, porcelain, alumina, silica, silicon carbide, glass. 
   It will be appreciated that the melting point of either shrinking layer  34  and/or bending layer  36  can be modified by the addition of a compound to alter the melting point of the particular layer. Examples of such compounds include carbon black, indocyanine green, methylene blue, titanium oxide, because they preferentially absorb energy at certain energy wavelengths. In particularly preferred embodiments, shrinking layer  34  is formed of a material which comprises from about 0.1-2.0% by weight titanium oxide, and preferably from about 0.25-0.75% by weight titanium oxide, based upon the total weight of the material taken as 100% by weight. Of course, those skilled in the art will appreciate that the type and quantity of energy-absorbing dye utilized can be altered depending upon the desired application. 
   The device  30   c  is preferably formed by co-extruding the materials of which the respective layers are formed, but may also be formed by bonding the layers together through solvents, pressure, or other physical methods. Regardless, layers  34 ,  36  will be bonded to one another at location  38  so as to form device  30   c . A barrier layer (not shown) can also be applied to the outer surface  40  of shrinking layer  34  to protect the tissue adjacent layer  34  from damage during heating thereof. The barrier layer should also be formed of a high melting point, bendable material such as those described with respect to bending layer  36 . 
   In the embodiment depicted, shrinking layer  34  has a thickness of from about 0.125-1.50 mm, and preferably from about 0.25-0.75 mm, while bending layer  36  has a thickness of from about 0.125-1.50 mm, and preferably from about 0.50-1.00 mm. Furthermore, the width of the illustrated devices  30   a - d  at their respective widest points is from about 1.0-4.0 mm, and preferably from about 1.5-3.0 mm. In embodiments where devices  30   a - d  are curved, the radius of curvature should be from about 7-10 mm so that the curve is substantially similar to the curvature of most human sclera at the site of device placement. Finally, it is preferred that the length of the devices  30   a - d  at their respective longest points be such that the devices  30   a - d  can fit into a sclera pocket  28   a - d  having a length of from about 3-8 mm, and preferably about 4.5 mm. 
   After placement of the devices  30   a - d , the accommodative ability of the eye is measured according to known methods (e.g., by measuring the accommodative amplitude or by stigmatoscopy). External energy is then applied to each of the devices  30   a - d . The source of energy is not critical, so long as it can be applied with sufficient intensity to cause layer  34  to shrink or contract. At the same time, the energy should be provided with a sufficiently low intensity so as to minimize, and preferably prevent, layer  36  from melting or shrinking as well as to avoid damage to the eye tissue surrounding the devices  30   a - d.    
   Types of energy sources which can be utilized include UV sources, IR sources, radio frequency emitters, heat, and low voltage DC and low voltage high frequency sources. However, the most preferred energy source is a laser  42  of the type typically utilized by an opthalmologic surgeon. The identity, intensity, and duration of the application of the laser used to adjust the devices  30   a - d  can be readily selected by a person of ordinary skill in the art. Preferred lasers include diode IR (which have a wavelength of about 805 nm) and argon (argon blue which has a wavelength of about 488 nm, argon green which has a wavelength of about 514.5 nm, or a combination of the two) lasers. However, any of the following lasers can be used as well: carbon dioxide; helium-neon; helium-cadmium; argon ion; krypton ion; xenon ion; nitrous oxide; iodine; holmium-doped yttrium-aluminum garnet; yttrium lithium fluoride; excimer; chemical; harmonically oscillated; dye; nitrogen; neodymium; erbium; ruby; and titanium-sapphire. With any of these types of lasers, the duration of treatment is typically from about 0.5-5.0 seconds while focusing on a location having a diameter of from about 300-500 μm. 
   After energy treatment, the accommodative ability of the eye  10  is again measured to determine whether further energy treatment is necessary. If it is, additional energy is applied as described above, and the accommodative ability is again measured with these steps being repeated as needed until the desired accommodation is obtained. 
   Referring to  FIGS. 4-5  it can be seen that the use of laser  42  to apply energy to shrinking layer  34  causes layer  34  to melt, and thus shrink or pull in a direction away from layer  36 , causing layer  35  to pull toward layer  34 . This “pulling” causes controlled, directional bending of the device  30   c  and, in turn, of the sclera  12 . As the shrinking of layer  34  causes the device  30   c  to bend in a direction away from the eye, the sclera is altered so as to increase the effectiveness of the accommodative apparatus of the eye. Phantom lines  44  in  FIG. 5  depict the curvature of layers  34 ,  36  and sclera  12  prior to energy application. 
   Advantageously, unlike prior art devices, devices according to the instant invention can be adjusted after placement thereof without subjecting the patient to further surgery. Thus, as the presbyopic condition worsens over time (e.g., about 2 years to 10 years after insertion), the patient can return to the surgeon who inserted the device, or to any other surgeon with an available energy-applying apparatus, and have the device further adjusted until acceptable accommodative levels are achieved. 
   It will be appreciated that in some applications direct application of energy to layer  34  may create problems (e.g., pitting, bubbling, or irregular melting of the shrinking layer  34 ). In these instances, it is generally desirable to apply the energy to bending layer  36 , allowing it to be an energy source for the less tolerant shrinking layer  34 . This allows for a more uniform heat dispersion along and through shrinking layer  34 , thus minimizing or avoiding problems with the material of shrinking layer  34  as well as minimizing or substantially preventing damage to the surrounding tissue. 
   The potential amount of shrinkage available to shrinking layer  34  can be increased during manufacturing by stretching or pulling the material of which shrinking layer  34  is formed prior to cooling and hardening. This will result in an increase in the amount of stress energy of the material and thus an increase in the material shrinkage. Additionally, the shrinkage can be controlled by the selection of the melt index of the material. 
   While the invention has been discussed with respect to the use of generally rectangular, slightly curved devices  30   a - d  in an eye  10  for treatment of presbyopia, it should be understood that the invention is not so limited. For example, the size and shape of device  30  can be altered depending upon the shape and location of the area in which it will be used. Thus, device  30  can be configured to alter the physical geometry of other human or animal body part (e.g., tissues, organs, veins, arteries, etc.) as necessary to treat a particular condition. Furthermore, rather than several small segments of the device, one larger or ringed segment could be utilized, as well as flat panels with adjustable vanes or flaps to act as valves. 
   The inventive device could also be used to open blocked veins or arteries by placing the device on or within the vein or artery and applying energy to the device so that directional bending occurs, thus expanding or closing the vein or artery. Advantageously, the invention allows for incremental expansion or closure of the vein or artery with subsequent additional expansion or closure being possible as needed. The device could also be used to incrementally increase or decrease the flow of fluid from the brain through a shunt in a patient suffering from hydrocephalus. 
   Although the inventive device has been discussed as a treatment for presbyopia, it can be used to treat any eye condition which is treatable by changing the shape or positions of the component structures of the eye and their functional relationship to each other. The device can also be used in eye drainage valves which bypass the trabecular meshwork. This would be accomplished by inserting a closed valve having the device disposed therein, and incrementally subjecting the device to applied energy so that the valve is opened or closed by small degrees until the desired flow level is obtained. 
   Furthermore, the device could be used to treat myopia or hyperopia by utilizing a ring-shaped device or partial ring-shaped devices (e.g., 140° rings). In this embodiment, the devices would be inserted into the cornea with the shrinking layer facing outwardly from the eye so that the cornea is “flattened” upon shrinkage of the device to treat myopia. To treat hyperopia, the devices would be inserted into the cornea with the shrinking layer facing inwardly from the eye. The non-shrinking layer is necessary to give directional control of the bending as well as to act as an energy source for the melting layer. 
   Finally, although the illustrated embodiment depicts a device according to the invention inserted in a sclera pocket, it should be understood that it may be desirable to attach the device to the surface of the body part to be treated. For example, the device could be sutured or glued with a biocompatible adhesive to the outer surface of the sclera. 
   EXAMPLES 
   A device according to the invention was formed by co-extruding two PMMA layers. A first layer was formed of PMMA having an ASTM D-1238 melt index of 1.1 and carbon black dye added thereto. A second layer was formed of PMMA having an ASTM D-1238 melt index of 6.6 and having titanium oxide added thereto. Five devices were formed with the following dimensions, respectively: two samples each designated as Sample 1-0.33 mm×0.66 mm×10 mm; and two samples each designated as Sample 2 and one sample designated as Sample 3-0.66 mm×0.66 mm×10 mm. 
   Multiple diode laser treatments were carried out by subjecting the first layer (having a black dye incorporated therein) of one specimen of each of Samples 1 and 2 to laser energy and then repeating the energy application to the second layer (having a white dye incorporated therein) of the same specimens of Samples 1 and 2. With Sample 3, the first layer (having a black dye incorporated therein) followed by the second layer (having a white dye incorporated therein) was subjected to multiple laser applications along its length, with the direction of bend and change in length being noted. 
   The laser parameters were chosen to maximize the change in shape of the device while minimizing focal deformity. The length of each sample was determined (with Vernier Callipers) after the first, third, fifth, seventh, and ninth laser treatments. These results are reported in Tables 1-3. The direction of bend was either toward the first or black layer (designated “B”) or toward the second or white layer (designated “W”). 
   
     
       
             
           
             
             
             
             
             
           
         
             
               TABLE 1 
             
             
                 
             
             
               Sample 1 (0.33 × 0.66 mm Specimens) 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                 
               Laser 
                 
               Laser 
                 
             
             
                 
                 
               Application 
                 
               Application 
             
             
                 
                 
             
             
                 
               Intensity (mW) 
               60 
                 
               50 
             
             
                 
               Spot Size 
               300 
                 
               500 
             
             
                 
               (microns) 
             
             
                 
               Duration 
               5000 
                 
               9000 
             
             
                 
               (milliseconds) 
             
             
                 
               Laser 
               Applied To 
               Bend 
               Applied To 
               Bend 
             
             
                 
                 
               Black 
                 
               White 
             
             
                 
               Treatment 
               (first layer) 
               Direction 
               (second layer) 
               Direction 
             
             
                 
                 
             
             
                 
                 
               Length Change 
                 
               Length Change 
             
             
                 
                 
               (mm) 
                 
               (mm) 
             
             
                 
                 
             
             
                 
               1 st   
               .000 
                 
               .020 
               B 
             
             
                 
               3 rd   
               .005 
               B 
               .030 
               B 
             
             
                 
               5 th   
               .010 
               B 
               .050 
               B 
             
             
                 
               7 th   
               .010 
               B 
               .075 
               B 
             
             
                 
               9 th   
               .015 
               B 
               .090 
               B 
             
             
                 
               Total Change 
               0.015 
               B 
               0.90 
               B 
             
             
                 
               (mm) 
             
             
                 
                 
             
           
        
       
     
   
   
     
       
             
           
             
             
             
             
             
           
         
             
               TABLE 2 
             
             
                 
             
             
               Sample 2 (0.33 × 0.66 mm Specimens) 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                 
               Laser 
                 
               Laser 
                 
             
             
                 
               Application 
                 
               Application 
             
             
                 
             
             
               Intensity (mW) 
               50 
                 
               160 
             
             
               Spot Size 
               500 
                 
               300 
             
             
               (microns) 
             
             
               Duration 
               9000 
                 
               9000 
             
             
               (milliseconds) 
             
             
                 
               Applied To 
               Bend 
               Applied To 
               Bend 
             
             
                 
               Black 
                 
               White 
             
             
                 
               (first layer) 
               Direction 
               (second layer) 
               Direction 
             
             
                 
             
             
                 
               Length Change 
                 
               Length Change 
             
             
                 
               (mm) 
                 
               (mm) 
             
             
                 
             
             
               1 st   
               .010 
                 
               .005 
               W 
             
             
               3 rd   
               .015 
               B 
               .035 
               W 
             
             
               5 th   
               .015 
               B 
               .055 
               W 
             
             
               7 th   
               .015 
               B 
               .085 
               W 
             
             
               9 th   
               .020 
               B 
               .110 
               W 
             
             
               Total Change 
               0.20 
               B 
               0.110 
               W 
             
             
               (mm) 
             
             
                 
             
           
        
       
     
   
   
     
       
             
           
             
             
             
           
             
             
             
             
           
         
             
               TABLE 3 
             
             
                 
             
             
               Sample 3 (0.66 × 0.66 mm Specimen 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                 
               Laser Application 
             
             
                 
                 
             
           
        
         
             
                 
               Intensity (mW) 
               60 
                 
             
             
                 
               Spot Size (microns) 
               500 
             
             
                 
               Duration 
               6000 
             
             
                 
               (milliseconds) 
             
             
                 
               Laser Treatment # 
               Applied To Black 
               Bend Direction 
             
             
                 
                 
               (first layer) 
             
             
                 
                 
             
             
                 
                 
               Length Change 
             
             
                 
                 
             
             
                 
               7 th   
               .015 
               B 
             
             
                 
               Intensity (mW) 
               320 
             
             
                 
               Spot Size (microns) 
               300 
             
             
                 
               Duration 
               500 
             
             
                 
               (milliseconds) 
             
             
                 
               Laser Treatment # 
               Applied To White 
             
             
                 
                 
               (second layer) 
             
             
                 
               7 th   
               0.290 
               W