Abstract:
Apparatus and methods for demonstrating to a patient the effects of anti-reflective (AR) coatings on the patient&#39;s eyeglass lens prescription. The apparatus comprises a refractor, or a retrofit kit for a refractor, wherein at least the strong and weak sphere lenses are provided with a high index of refraction (IR) and are treated with an anti-reflective coating producing a high light transmission (LT) percentage and a low reflectance per surface (RPS) percentage. The apparatus further includes at least one filter which is removably placeable in viewing alignment with the viewing tube of the refractor. The filter is selected to have an IR, LT value and RPS value which, when disposed in alignment with the viewing tube in combination with any of the strong and/or weak sphere lenses produces a net LT value and net RPS value corresponding to the lenses to be used in the patients eyeglass lens without an AR coating treatment.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of, and priority to, U.S. Provisional Application No. 60/611,638 filed Sep. 21, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The chart of  FIG. 7  identifies some of the various types of materials commonly used for eyeglass lenses. As identified in the chart, each of these materials has a known or definable index of refraction (“IR”), as well as a known or definable percentage of light transmittance (“LT”) and light reflectance per surface (“RPS”) for a given light wavelength. The values of the IR, LT and RPS identified in  FIG. 7 , are based on a light wavelength of 550 nm.  
         [0003]     It should be understood that the higher a lenses LT percentage and the lower the lenses RPS percentage, the more light will pass through the lens to the eyes of the wearer and the less reflectance the wearer will experience. Thus, lenses with lower LT percentages and higher RPS percentages will cause the eyeglass wearer to receive less visible light and experience more internal and external light reflection through the lenses, which may result in mirror effects, ghost image effects and glare. Such effects are often pronounced with neon lights, when viewing computer or television screens or by vehicle headlights at night, causing discomfort and eye fatigue to the eyeglass wearer.  
         [0004]     Thus, it should be appreciated that lenses with a high LT percentage and with a low RPS percentage are more desirable for eyeglasses. Of the lens materials identified in the chart of  FIG. 7 , glass and CR 39® have the highest LT percentage and the lowest RPS percentages. While these materials have good optical qualities for lenses, glass is a relatively heavy and brittle material. CR39® although lighter in weight and less brittle than glass, generally requires greater lens thicknesses to achieve a desired corrective lens prescription. In an effort to meet consumer demand for thinner and lighter weight lenses for eyeglasses, lens manufacturers began producing lenses from polycarbonates, hi-index plastics, hi-index glass and more recently super hi-index glass. Unfortunately, the LT percentages are generally lower and the RPS percentages generally higher with these higher-index materials than with glass and CR39®. However, as identified in the chart of  FIG. 7 , by coating the higher-index materials with a multi-layer anti-reflective (“AR”) coating, such as the Super ET® coating offered by Carl Zeiss, Inc. or other suitable AR coating treatment, the LT percentages and RPS percentages can be improved to meet or exceed the LT percentages and RPS percentages of glass and CR39® lenses.  
         [0005]     Unfortunately, in the United States, only approximately twenty percent (20%) of all eyeglass lenses dispensed receive AR coatings despite the substantial benefits achieved with AR coatings. In other countries and regions, however, the majority of eyeglasses sold receive AR coatings. In Europe, for example, approximately seventy five percent (75%) of all eyeglass lenses dispensed receive AR coatings. In Japan, approximately ninety percent 90% of all eyeglass lenses dispensed receive AR coatings.  
         [0006]     The reasons for such a low percentage of AR coated eyeglass sold in the United States, as opposed to other countries, may be due, in part, to the additional cost for AR coated lenses, as well as due to the lack of capital investment needed by the laboratories that process lens prescription orders to acquire the equipment and materials required to apply AR coatings to the lenses they process. However, it is submitted that the dominant reason many individuals elect not to purchase AR coated lenses for their eyeglasses is due to the fact that, heretofore, there has been no way for individuals to truly compare, at the point of sale, the difference in visual acuity between lenses with and without AR coatings. It is submitted that if most individuals are given the opportunity to truly experience the improvement in visual acuity achieved with AR coated lenses over non-AR coated lenses, most individuals will elect to receive AR coating treatment on their eyeglass lenses despite the increased cost.  
         [0007]     Heretofore, optometrists, ophthalmologists and representatives of eyeglass retailers had to try to persuade their patients or customers to elect AR coatings on their lens by attesting to the benefits of AR coatings and relying on various types of point-of-sale displays including visual aids and demonstrative exhibits. Needless to say, most individuals who have not previously experienced the benefits of AR coating on their eyeglass lenses, are somewhat cynical when, at the point-of-sale, they are presented with a perceived “sales pitch” from the practitioner, and particularly from a sales representative of the retail store sales representative, touting the purported benefits of AR coating.  
         [0008]     The cynicism of the customer is not dispelled by the currently available point-of-sale displays purporting to demonstrate the advantages of AR coated lenses. One type of point-of-sale display includes a photograph purporting to show the difference in visual acuity between side-by-side lenses, one having an AR coating and the other without. Another purports to demonstrate the cosmetic benefits of AR coated lenses, by a photograph showing a person wearing glasses with one lens, purporting to be the AR coated lens, appearing vary clear and transparent and the other lens, the non-AR coated lens, showing a glaring reflection so that the person&#39;s eye is not even visible. Yet another type of demonstrative exhibit that has been employed in the industry for promoting AR coatings at the point-of-sale is to provide a sample lens with one half of the lens treated with an AR coating. The problem with this type of demonstrative exhibit, however, is that it often raises the level of cynicism of the customer in that the lens half without the AR coating is usually scratched, smudged or is perceived by the customer as being an inferior quality lens, and thus does not accurately represent how the AR coating will truly benefit the customer with his/her particular lens prescription.  
         [0009]     Accordingly, there is a need for apparatus and methods for demonstrating to individual prospective customers the benefits of applying AR coating to their eyeglass lenses which overcomes the cynicism and shortcomings associated with current apparatus and methods which purport to demonstrate the benefits of AR coatings on eyeglasses lenses.  
       SUMMARY OF THE INVENTION  
       [0010]     Apparatus and methods for demonstrating to a patient the effects of anti-reflective (AR) coatings on the patient&#39;s eyeglass lens prescription. The apparatus comprises a refractor, or a retrofit kit for a refractor, wherein at least the strong and weak sphere lenses are provided with a high index of refraction (IR) and are treated with an anti-reflective coating producing a high light transmission (LT) percentage and a low reflectance per surface (RPS) percentage. The apparatus further includes at least one filter which is removably placeable in viewing alignment with the viewing tube of the refractor. The at least one filter selected to have an IR, LT value and RPS value which, when disposed in alignment with the viewing tube in combination with any of the strong and/or weak sphere lenses produces a net LT value and net RPS value corresponding to the lenses to be used in the patients eyeglass lens without an AR coating treatment. The methods comprise the steps for demonstrating to a patient the effects of AR coatings on the patient&#39;s eyeglass lens prescription and methods for retrofitting refractors to enable such demonstrations.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a front view of a conventional refractor in which a preferred embodiment of the apparatus of the present invention is embodied, wherein the right eye battery is shown partially broken away to reveal internal gearing and support interconnecting the batteries.  
         [0012]      FIG. 2  is a cross-sectional view of the right eye battery taken substantially along line  2 - 2  of  FIG. 1 , illustrating the right eye sphere lens assembly in elevation and the cylinder lens assembly and cross cylinder arrangement in cross-section.  
         [0013]      FIG. 3  is a sectional view of the right eye battery as viewed along line  3 - 3  of  FIG. 1 , illustrating the right eye sphere assembly partially in section, the cylinder lens assembly in section and the cross cylinder arrangement partially in section.  
         [0014]      FIG. 4  is an exploded perspective view of the weak sphere lens carrier disk of the refractor of  FIG. 1 .  
         [0015]      FIG. 5  is an exploded perspective view of the strong sphere lens carrier disk of the refractor of  FIG. 1 .  
         [0016]      FIG. 6  is an exploded perspective view of the auxiliary lens carrier disk of the refractor of  FIG. 1 , illustrating the filters for use in the apparatus and method of the present invention disposed for insertion into one of the blank apertures and for insertion into cells in place of the red lens and the +0.12D lens.  
         [0017]      FIG. 7  is a chart identifying lens materials, and corresponding IR values, LT values, RPS values for the lens materials with and without AR-coating.  
         [0018]      FIG. 8  illustrates an alternative embodiment for locating the filters in viewing alignment with the viewing tube. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     Drawing  FIGS. 1 through 3  illustrate a refractor, designated generally by reference numeral  10 , of the type disclosed in U.S. Pat. No. 3,498,699 issued to Wilkinson (hereinafter the “Wilkinson &#39;699 patent”), which is hereby incorporated, in its entirety, by reference. A commercial embodiment of the refractor  10  disclosed in the Wilkinson &#39;699 patent is presently manufactured and distributed by Reichert Ophthalmic Instruments under the trademark Phoroptor® (hereinafter referred to as the “Reichert Refractor”). While the apparatus and methods of the present invention for demonstrating the effects of AR lens coatings is particularly disclosed with respect to the Reichert Refractor, it should be understood that the apparatus and methods of the present invention are equally applicable to other types of refractors, whether now known or later developed. As a result, the apparatus and methods of the present invention should not be construed as being limited to or for use with any particular type of refractor except as otherwise specifically defined in the appended claims.  
         [0020]     The refractor  10  includes a left eye battery  12  and a right eye battery  14 . The two batteries  12 ,  14  are essentially mirror images of one another, and therefore only the components of a single battery are hereinafter discussed in detail. In  FIG. 1 , the refractor  10  is illustrated from the front or practitioner&#39;s side of the instrument. The patient&#39;s side of the instrument is hereinafter referred to as the rear side. The left and right batteries  12 ,  14  of the refractor  10  are retained side by side by a support  16 . The support  16  permits desired manipulation of the batteries  12 ,  14  with respect to the patient&#39;s eyes and includes, generally, a yoke  17 , a support bridge  19  and a level  21 .  
         [0021]     The major component parts of each battery  12 ,  14  are illustrated in  FIGS. 2 and 3  and include a sphere lens assembly  18 , a cylinder lens assembly  20  and a cross cylinder arrangement  22 . Each of the batteries  12 ,  14  further includes a viewing tube  23 . When in use, the patient&#39;s head is positioned to the rear of the instrument so that the patient&#39;s left and right eyes are positioned in substantial alignment with the left and right viewing tubes  23  of the respective left and right batteries  12 ,  14 .  
         [0022]     The sphere lens assembly  18  is best illustrated in  FIGS. 2 and 3  and includes a sphere lens housing  24  in which a pair of lens carrier discs  26 ,  28  are coaxially rotatably mounted. The housing  24  includes a viewing aperture  27  which defines the rear end of the viewing tube  23 . With reference to  FIGS. 2 and 3 , the forward-most lens carrier disc  26  carries a set of weak sphere lenses  30  and is therefore typically referred to in the industry as the “weak sphere disk.” As best illustrated in  FIG. 4 , which is an exploded perspective view of the weak sphere carrier disk  26 , the disk includes a circular array of radially spaced cells  32 , each successive cell  32  supporting an incrementally graded weak sphere lens  30 . Typically one of the cells  32  is left vacant thereby defining a blank aperture  34 . The rearward-most lens carrier disc  28  as illustrated in  FIGS. 2 and 3  carries a set of strong sphere lenses  36  ( FIG. 5 ) and is therefore typically referred to in the industry as the “strong sphere disk.” As best illustrated in  FIG. 5 , which is an exploded perspective view of the strong sphere carrier disk  28 , the disk includes a circular array of radially spaced cells  38 , each successive cell  38  supporting an incrementally graded strong sphere lens  36 . Typically one of the cells  38  is left vacant thereby defining a blank aperture  40  ( FIG. 4 ). The lenses  30 ,  36  of the lens carrier discs  26 ,  28  as well as the blank apertures  34 ,  40  are selectively and successively rotatable into viewing alignment with the viewing tube  23 .  
         [0023]     The sphere lens assembly  18  further includes an auxiliary lens carrier disc  42  disposed coaxial with the sphere lens discs  26 ,  28 . The auxiliary disc  42  also includes a plurality of cells  44  as best illustrated in  FIG. 6  which is an exploded perspective view of the auxiliary lens carrier disk  42 . In the Reichert Refractor embodiment, two of the cells  44  are left vacant thereby defining blank apertures  46 ,  48 . The remainder of the cells  44  typically support different types of auxiliary lenses including a red lens  50  and +0.12 diopter lens  52 . As with the sphere lens discs  26 ,  28 , the auxiliary lens disk  42  is also rotatable within the housing  24  such that each of the cells  44  can be selectively and successively rotated into viewing alignment with the viewing tube  23 .  
         [0024]     The selection of the desired cells  32 ,  38 ,  44  of the weak sphere disk  26 , strong sphere disk  28  and auxiliary lens disk  42 , respectively, for viewing alignment with the viewing tube is controlled, by rotation of the respective carrier disk. The weak sphere lens disc  26  is rotated by direct contact with its exposed knurled edge  54 . The strong sphere lens carrier disk  28  is rotated by turning the strong sphere lens control knob  56 . The auxiliary lens carrier disk is rotated by turning the auxiliary lens control knob  58 . The internal structural components to effect the rotation of the disks  26 ,  28 ,  42  is more fully disclosed in U.S. Pat. No. 2,999,065, also incorporated herein by reference, in it entirety.  
         [0025]     The construction and operation of the cylinder lens assembly  20  and cross cylinder arrangement  22  for the refractor  10  is fully set forth in the Wilkinson &#39;699 patent, and in U.S. Pat. No. 2,968,213, also incorporated herein by reference, in it entirety. As such, no further discussion of the construction and operation of the refractor  10  in connection with the cylinder lens assembly  20  and cross cylinder arrangement  22  is provided herein; it being understood, however, that the construction and operation of the cylinder lens assembly  20  and cross cylinder arrangement  22  and all other features and functionalities of the refractor  10  as disclosed in Wilkinson &#39;699 and the foregoing &#39;065 and &#39;213 patents, are to be considered disclosed herein as if expressly reprinted herein.  
         [0026]     In the preferred embodiment of the apparatus of the present invention, the material used for the lenses  30 ,  36  of the weak and strong sphere disks  26 ,  28  and for any of the other lenses comprising the cylinder lens assembly  20  and cross cylinder arrangement  22 , is preferably Super Hi-Index Glass with an IR value of 1.8 or greater. The lenses are treated with a AR coating, such as with the Super ET® multi-layer AR coating offered by Carl Zeiss, Inc. or some other suitable AR coating treatment. It should be appreciated, therefore, that with all of the lenses in the refractor  10  made of a material with one of the highest available indexes of refraction, and with each of the lenses treated with an AR coating, with the appropriate combination of lenses selected to correct the patient&#39;s vision deficiencies, the patient will be able to view a reference object through the viewing tube  23  under conditions approaching the greatest visual acuity possible with the patient&#39;s lens prescription.  
         [0027]     In order to demonstrate to the patient the beneficial effects of the AR coating on the patient&#39;s eyeglass lenses, the perceived effects of the AR coating are removed from the lenses aligned in the viewing tube  23  by placing a filter into viewing alignment with the viewing tube  23 . The filter acts to reduce the amount of light transmission through the viewing tube and increases the amount of light reflectance perceived by the patient so as to provide to the patient an accurate representation of the difference in visual acuity likely to be experienced if he/she elects to not receive AR coating on his/her prescribed lenses.  
         [0028]     In the preferred embodiment, three filters  100 ,  102 ,  104  are preferably available for selection by the practitioner to provide the appropriate “corrections” to the IR value, LT value and RPS value of the AR coated lenses so as to accurately represent the patient&#39;s eyeglass lenses without an AR coating. Thus, as illustrated in  FIG. 7 , a first filter  100  preferably has an IR value, LT value and RPS value to produce a net IR value, net LT value and net RPS value in combination with the AR-coated lenses of the refractor  10  corresponding to the non-AR coated IR values, LT values and RPS values for glass and CR39® lens materials. The second filter  102  preferably has an IR value, LT value and RPS value to produce a net IR value, net LT value and net RPS value in combination with the AR-coated lenses of the refractor  10  corresponding to the non-AR coated IR values, LT values and RPS values for Polycarbonate, Hi-Index Glass (1.6) and Hi-Index Plastic lens materials. The third filter  104  preferably has an IR value, LT value and RPS value to produce a net IR value, net LT value and net RPS value in combination with the AR-coated lenses of the refractor  10  corresponding to the non-AR coated IR values, LT values and RPS values for Super Hi-Index Plastic and Hi-Index Glass (1.7).  
         [0029]     It should be understood that only three filters as defined above are deemed necessary to provide the correction factors for each of the seven different materials presently used for eyeglass lenses. This is due to the fact that IR values, LT values and RPS values are so closely aligned when grouped as illustrated in  FIG. 7  that any differences would likely not be perceptible to the patient.  
         [0030]     In the preferred embodiment, the three filters  100 ,  102  and  104  are preferably disposed on the auxiliary lens carrier disk such that the filters can be selectively rotated into viewing alignment with the viewing tube by the practitioner rotating the auxiliary lens control knob  58  as previously described. With respect to the Reichert Refractor embodiment, one of the three filters  100 ,  102 ,  104  is preferably disposed in one of the blank apertures  46 ,  48 , with the remaining two filters  102 ,  104  inserted into the cells  44  previously supporting the red lens and +0.12 diopter lens  52 , which are rarely used by practitioners, and thus will not likely be missed by practitioners. Thus, it should be appreciated that by inserting the filters  100 ,  102 ,  104  into existing cells  44  in the auxiliary lens carrier disk  42 , no cutting or other physical modification of the disk  42  is necessary, except to remove certain of the disk&#39;s existing lenses insertion of the filters into the available cells  44 .  
         [0031]     As an alternative embodiment, the filters  100 ,  102 ,  104  may be separate members adapted to be placed over the viewing tube, at the front or rear of the instrument, or both. As illustrated in  FIG. 8 , in such an alternative embodiment, a socket  70  may secured to the refractor, at the front or rear of the instrument or both, into which the filters  100 ,  102 ,  104  may be slidably inserted.  
         [0032]     Using the foregoing preferred embodiment of the apparatus of the present, a preferred method of demonstrating effects of AR coatings on lenses to a patient is performed by the practitioner after the appropriate corrective lenses of the patient have been selected and with the selected AR-coated lenses still disposed in viewing alignment with the viewing tubes  23  of the right and left batteries  12 ,  14 . With the patient looking through the viewing tubes, the practitioner selectively rotates the auxiliary lens carriers  42  so as to position in viewing alignment with each viewing tube  23 , one of the filters  100 ,  102 ,  104  having the properties which will resulting in the net IR value, net LT value and net RPS value corresponding to the non-AR coated IR value, LT value and RPS value of the type of lenses to be used for the patient&#39;s prescription eyeglasses. With the patient continuing to look through the viewing tubes  23 , the practitioner selectively rotates the auxiliary lens carriers  42  so as to remove the previously selected filters  100 ,  102 ,  104  from viewing alignment with the viewing tubes  23 , whereupon the patient will again be able to perceived the reference object through the viewing tube  23  through the AR-coated lenses under the AR-coated IR value, the AR-coated LT value and AR-coated RPS value of the lenses. The foregoing steps can be repeated in succession as many times as necessary to enable the patient to compare the difference in visual acuity and other perceived effects with lens treated with an AR coating versus an accurate representation of the visual acuity and effects likely to be experienced with the same prescription lenses not treated with an AR coating.  
         [0033]     As an alternative method of demonstrating the effects of AR-coated lenses, with respect to the alternative embodiment, instead of the practitioner rotating the auxiliary lens carrier with the filters disposed therein, the practitioner may simply insert the corresponding filter into the socket.  
         [0034]     Although only certain exemplary embodiments of the apparatus and methods of present invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.