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Title:
CONTACT LENS CLEANING COMPOSITION AND METHOD OF USE
Document Type and Number:
WIPO Patent Application WO/1988/005073
Kind Code:
A1
Abstract:
Contact lens cleaning compositions containing a combination of an enzyme and a particulate abrasive material, and a method of cleaning contact lenses with such compositions. The compositions are capable of cleaning soiled contact lenses very rapidly and completely due to a favorable interaction between the enzyme and abrasive components thereof.

Inventors:
BHATIA RAJKUMAR P (US)
HARRIS ROBERT G (US)
Application Number:
PCT/US1987/003396
Publication Date:
July 14, 1988
Filing Date:
December 23, 1987
Export Citation:
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Assignee:
ALCON LAB INC (US)
International Classes:
G02C13/00; C11D3/00; C11D3/386; C11D17/00; (IPC1-7): C11D7/42
Foreign References:
US4067773A1978-01-10
US4534878A1985-08-13
US4609493A1986-09-02
US4710313A1987-12-01
Other References:
See also references of EP 0298105A4
Download PDF:
Claims:
What is Claimed is:
1. A composition for cleaning a contact lens, comprising an ophthalmically acceptable enzyme in an amount sufficient to facilitate chemical decomposition and removal of deposits from the lens; a particu¬ late abrasive material in an amount sufficient to facilitate physical removal of deposits and debris present on the lens; and an ophthal¬ mically acceptable carrier therefor.
2. A composition according to Claim 1, wherein the enzyme comprises at least one enzyme having proteolytic activity, lipolytic activity, or a combination of proteolytic and lipolytic activity.
3. A composition according to Claim 1, wherein the enzyme is selected from proteolytic and lipolytic enzymes of plant, animal, bacterial, fungal or synthetic origin.
4. A composition according to Claim 1, wherein the enzyme comprises pancreatin.
5. A composition according to Claim 1, wherein the enzyme is contained in the composition in an amount of from about 0.1% to about 50.0% by weight.
6. A composition according to Claim 1, wherein the particulate abrasive material is selected from solid organic and inorganic materials.
7. A composition according to Claim 6, wherein the particulate abrasive material is selected from organic polymers and polysiloxane polymers.
8. A composition according to Claim 6, wherein the particulate abrasive material comprises an inorganic material.
9. A composition according to Claim 8, wherein the inorganic material is selected from aluminas, aluminum silicates, magnesium silicates, magnesium carbonate, magnesium oxide, calcium carbonate, titanium dioxide, zirconium dioxide, cerium oxide, cesium oxide, barium sulfate, lentonite, pumice, silicon dioxide, sodium chloride, potassium chloride, sodium bicarbonate, and binary mixtures of sodium chloride and sodium bicarbonate.
10. A composition according to Claim 1, wherein the particulate abrasive material is contained in the composition in an amount of from about 0.1% to about 25% by weight.
11. A method' of cleaning a contact lens which comprises contacting the lens with the composition of Claim 1.
12. A twopart composition for cleaning a contact lens, comprising a first part containing an ophthalmically acceptable enzyme in an amount sufficient to facilitate chemical decomposition and removal of deposits from the lens; and a second part containing an ophthalmically accept able, particulate abrasive material in an amount sufficient to facili¬ tate physical removal of deposits and debris present on the lens, and an ophthalmically acceptable carrier for said enzyme and said particulate abrasive material; wherein the first part and the second part are packaged in separate containers prior to initial use of said composition.
13. A twopart composition according to Claim 12, wherein the enzyme comprises at least one enzyme having proteolytic activity, lipolytic activity, or a combination of proteolytic and lipolytic activity.
14. A twopart composition according to Claim 12, wherein the enzyme is selected from proteolytic and lipolytic enzymes of plant, animal, bacterial, fungal or synthetic origin.
15. A twopart composition according to Claim 12, wherein the enzyme comprises pancreatin.
16. A twopart composition according to Claim 12, wherein the enzyme is contained in the first part of the composition in an amount of from about 0.1% to about 50.0% by weight.
17. A twopart composition according to Claim 12, wherein the particulate abrasive material is selected from solid organic and inorganic materials.
18. A twopart composition according to Claim 17, wherein the particulate abrasive material is selected from organic polymers and polysiloxane polymers.
19. A twopart composition according to Claim 17, wherein the particulate abrasive material comprises an inorganic material.
20. A twopart composition according to Claim 19, wherein the inorganic material is selected from aluminas, aluminum silicates, magnesium sili¬ cates, magnesium carbonate, magnesium oxide, calcium carbonate, titanium dioxide, zirconium dioxide, cerium oxide, cesium oxide, barium sulfate, lentonite, pumice, silicon dioxide, sodium chloride, potassium chloride, sodium bicarbonate, and binary mixtures of sodium chloride and sodium bicarbonate.
21. A twopart composition according to Claim 12, wherein the particulate abrasive material is contained in the composition in an amount of from about 0.1% to about 25% by weight.
Description:
CONTACT LENS CLEANING COMPOSITION AND METHOO OF USE

Background of the Invention

1. Field of the Invention

The present invention relates to the field of contact lens care. More particularly, this invention relates to a new product for cleaning contact lenses which comprises an enzyme component and an abrasive component.

2. Discussion of Related Art

The cleaning of human-worn contact lenses is a problem which has been addressed in numerous prior art patents and other publications.

Many of the previous attempts to solve this problem have focused on the use of particular types of surfactants; the following patents represent examples of such attempts: U.S. Patent Nos. 3,882,036; 3,954,644; 4,046,706; and 4,599,195. The use of enzymes has also been proposed as a solution to this problem; U.S. Patent Nos. 3,910,296; 3,954,965; 4,096,870; 4,521,254; and 4,609,493 describe this approach. A rela¬ tively recent approach addressing the cleaning problem utilizes poly¬ meric particles as an abrasive material to physically remove deposits from the surface of the lens; this approach, which has been relatively successful, is described in U.S. Patent No. 4,493,783. U.S. Patent Nos. 4,394,179 and 4,534,878 describe approaches wherein inorganic abrasive materials are utilized. U.S. Patent No. 4,533,399 describes the use of a fibrous web to clean contact lenses.

There have been numerous other attempts to solve the cleaning problem in addition to those cited above. The following U.S. patents may be referred to for additional background information in this regard: 4,127,423; 4,357,173; 4,421,665; 4,440,662; 4,500,441; and 4,504,405.

A new approach to the cleaning problem is described in the copending and commonly assigned application of Van Duzee titled "CONTACT LENS CLEANING PRODUCT AND METHOD OF USE". This approach is based on the use of a nonwoven web impregnated with an enzyme to clean contact lenses.

Summary of the Invention

A principal object of the present invention is the provision of compositions capable of rapidly and completely removing deposits of proteins, lipids, and other materials from contact lenses. A further object of this invention is the provision of a method of cleaning contact lenses using such compositions.

The foregoing objects and other general objectives of the present invention are achieved by the provision of contact lens cleaning compo¬ sitions which comprise an enzyme to facilitate chemical decomposition and removal of deposits from contact lenses, particularly deposits of protein and lipid materials; a particulate abrasive material to facili¬ tate physical removal of such deposits; and a suitable carrier for the enzyme and abrasive material. It has been discovered that such compo¬ sitions are capable of removing deposits of proteins, lipids, and other materials from the surfaces of contact lenses in a very efficacious manner. The extent of cleaning achieved with these compositions is at least comparable with the cleaning achieved with cleaning compositions of the prior art, and in most cases is significantly better than the cleaning achieved with prior art compositions. The compositions of the present invention have been found to clean contact lenses much more rapidly than prior art compositions capable of providing a comparable extent of cleaning. The present compositions therefore represent a major advancement in the field of contact lens cleaning agents.

Description of Preferred Embodiments

The contact lens cleaning compositions of the present invention contain an amount of one or more enzymes sufficient to substantially , reduce deposits of proteins, lipids, and other materials on the lens

being treated. The amount of enzyme contained in the compositions will vary depending on factors such as the particular type of enzyme util¬ ized and the activity of that enzyme, the type of contact lens being treated, the cleaning regimen being employed (e.g., daily or weekly), and the concentration of other components in the compositions. The compositions of the present invention will typically contain from about 0.1% to about 50.0% by weight of one or more enzymes.

The enzymes which may be utilized in the present invention include all enzymes which are capable of removing deposits of proteins, lipids, and other materials from contact lenses safely and effectively. The

"safely" requirement means that the enzymes must be relatively nontoxic to the eye at low concentrations, so that only mild ocular irritation will occur if a small amount of enzyme is inadvertently placed in the eye as the result of inadequate rinsing of a treated lens. The enzymes must also be capable of being easily removed from treated lenses by means of rinsing, and must not damage the contact lens being treated. Enzymes which meet the foregoing requirements are referred.to. herein as being "ophthal ically acceptable". Those skilled in the art will appreciate that the enzymes are also required to be chemically compatible with the other components of the present compositions.

The enzymes utilized in the present invention will most frequently be enzymes having proteolytic and/or lipolytic activity, since deposits of proteins and lipids are formed on most, if not all, human worn con¬ tact lenses. Examples of suitable proteolytic enzymes include pan- creatin, papain, Prolase RH (available from G. B. Fermentation Corp.), ficin, and bro elain. Examples of suitable lipolytic enzymes include Lipase -3000 and Lipase APβ (available from A ano Corp.), and pancreatic lipase. Those skilled in the art will readily appreciate that other proteolytic and lipolytic enzymes of plant, animal, bacterial, fungal or synthetic origin might also be employed in the present invention. Certain enzymes may require the presence of a stabilizing agent, such as acetylcysteine. Other methods of enzyme stabilization, such as bound enzyme systems and microencapsulated enzyme systems, may also be utilized. In a preferred embodiment of tte

present invention, enzyme stabilization is generally not a concern because the enzyme component of the lens cleaning compositions is pack¬ aged separately from the other components prior to use and is then combined with the other components at the time of initial use. This approach avoids the need for long-term enzyme stability in order to provide the compositions with a shelf-life of several months or more (i.e., roughly 18 months, generally), since the enzyme only needs to be stable for a relatively short time following combination of the enzyme and abrasive components (i.e., roughly 1 to 14 days, or in some cases slightly longer). This embodiment of the invention is described in greater detail below.

The compositions of the present invention contain an amount of a particulate abrasive material sufficient to substantially reduce all deposits present on the surfaces of the contact lens being treated by facilitating physical removal of such deposits. The abrasive material component of the present compositions is particularly effective in removing loosely bound deposits from the surfaces of a lens, such as deposits of debris (e.g., lint) and cosmetic residues, as well as large deposits of proteins, lipids,. and other materials. The particulate abrasive material may comprise any solid organic or inorganic material capable of efficaciously abrading a soiled contact lens to remove deposits from the surfaces of the lens. The amount of abrasive material contained in the compositions will vary depending on factors such as the particular type of abrasive material utilized, the type of contact lens being treated (e.g., "hard" or "soft") and the cleaning regimen being employed. The compositions of the present invention will typically contain from about 0.1% to about 25% by weight of one or more abrasive materials.

There are numerous types of abrasive materials which may be utilized in the present invention. The primary requirements with respect to selection of a particular type of abrasive material are that the material be capable of removing deposits from contact lenses and be safe for ophthalmic use. The latter requirement means that the material must be nontoxic to the eye and will, at most, cause only

minor ocular discomfort or irritation in the event a small quantity of the material is accidentally placed in the eye as a result of inade¬ quate rinsing of a lens after cleaning. Two additional requirements with regard to selection of an abrasive material are that the material not damage the contact lens and that the material be capable of being easily rinsed from the lens after cleaning has been completed. Abra¬ sive materials which meet the foregoing requirements are referred to herein as being "ophthalmically acceptable". Finally, as will be appreciated by those skilled in the art, the abrasive material must be chemically compatible with the enzyme(s) contained in the composition being formulated, as well as the other components of the composition.

The preferred abrasive materials in the present invention are particulate organic and polysiloxane polymers of the type described in commonly assigned U.S. Patent No. 4,493,783. Other types of abrasive materials are described in U.S. Patent Nos. 4,394,179 and 4,588,444. Reference is made to these patents for further background and teaching regarding the use of abrasive materials in contact lens cleaning com¬ positions. The entire contents of these three patents are hereby incorporated in the present specification by reference.

U.S. Patent No. 4,493,783, describes the use of particulate organic and polysiloxane polymers as abrasive materials in compositions for cleaning soiled contact lenses. The specific polymers mentioned in this patent are set forth in Table A below. A preferred type of organic polymer for use in the present invention is poly (11-undecamide), which is also known as nylon 11.

Table A

Suitable Particulate Polymers*

True

Shore Rockwel1 Molecular Density

Polymer Hardness Hardness Weiqht (qm/mL) acrylonitrile-butadieπe- R75-115 β 1.04 styrene acetal or 1,1 diethoxyethane M94 polymethylmethacrylatε M85-105 12,000 2 1.20 1

(PMMA) methylmethacrylate/styrene M75 - - copolymer ethyl cellulose R50-115 - 1.14} cellulose acetate butyrate R30-115 - 1.25; cellulose acetate R85-120 - 1.30} polytetrafluoroethylene D50- -55 - 2.00 polychlorotrifluorεthylene R75-95 - - modified polyethylene- R50 - - tetrafluoroethylene (PE-TFE) ionomer D50- -65 - -

(copolymers of ethylene and methacrylic acid or polyethylene modified with methacrylic acid) fluoro ethylene polymer D50- -.65 - -

(FEP) fluoroplastic 1

Nylon 6 or poly R80-83 - 1.08 1

(caprolactam) 1

Nylon 6/6 or poly R114-120 - 1.14 1

(hexa ethylεne) adipamide

Nylon 11 or poly R108 - 1.04 1

(11-undecamide)

Nylon 12 or poly R106 - 1.01 1

(lauryl lactam) *

1 polybutadiene R40 200,000 1.01 1 to ^ 300,000 polyarylether R117 -_ polycarbonate M70 20,000 1.20 1 to . 25,000"

PBT polyester or poly M68-78 (butyl ene terephthal ate) M68-78

Continued

Table A - Continued

True

Shore Rockwell Molecular Density

Polymer Hardness Hardness Weight (qm/mL) polyethylene R50 1,500 0.91 to . to 4 100,000 0.94^ polypropylene R80 — 0.90 to 4 0.92? polysulfone R88 30,000 2 1.24: silicone A15-65 - 0.98 1

*ASTM test method 0785 applies to the Rockwell Hardness figure given, and ASTM test method D22450 applies to the Shore Hardness figures given.

Scientific Polymer Products Catalog 801

2

Average Molecular Weight

3 Molecular Weight Range

4 The Merck Index, Ninth Edition

5 The polymer backbone of the ionomers consists primarily of ethylene and a vinyl co onomer, such as methacrylic add, thus exhibiting pendant carboxyl groups. These linear chains are "cross-linked" by ionic, intermolecul r forces through incorporation of metallic cations from

Groups I or II of the periodic table. Thus, the network structure is formed by electrostatic forces similar to those in inorganic crystals rather than covalent bonds as found in typical thermosets. The cross¬ link density can be varied in these systems by copolymerization of various amounts of vinyl monomer with the ethylene and by varying the type and amount of metallic cations in the polymer. As with all the polymers, the physical properties are also influenced to some degree by the molecular weight distribution.

In addition to the above-mentioned polymeric materials, other polymeric materials such as polymers utilized in the manufacture of "soft" and "hard" contact lenses (i.e., lens polymers) may also be util- ized in the present invention. Examples of such polymers include poly- HEMA and silicon acrylates.

The above-mentioned polymeric materials are typically utilized as abrasive materials in an amount of from about 1% to about 25% by weight, with an average particle size in the range of about one to six hundred microns.

U.S. Patent No. 4,394,179,, describes the use of water insoluble, inorganic particles as abrasive materials in contact lens cleaning com¬ positions. The specific types of inorganic materials mentioned include aluminas (calcined, hydrated, tabular), aluminum silicates (kaolin), magnesium silicates (talc), magnesium carbonate, magnesium oxide, cal- ciu carbonate, titanium dioxide, zirconium dioxide, cerium oxide, cesium oxide, barium sulfate (barytes), bentonite, and pumice. These abrasive materials are utilized in an amount of from about 0.1% to about 10% by weight, and have an average particle size of no more than 20 microns.

U.S. Patent No. 4,588,444, describes the use of finely divided crystallizing powders to remove deposits from contact lenses. The specific types of powders mentioned include sodium chloride, sodium bicarbonate, and binary mixtures of sodium chloride and sodium bicarbon¬ ate. The powders have a particle size such that essentially all of the powder will pass through a 50 mesh screen and at least about 80% by weight of the powder will be retained on a 200 mesh screen.

Still further examples of suitable abrasive materials include cellulose and cellulose derivatives, silcon dioxide, and potassium chloride.

The compositions of the present invention further comprise a carrier which is compatible with both ocular tissue and the other components of the compositions, including the particulate material and enzyme com¬ ponents. Carriers which meet these requirements are referred to herein as being "ophthal lcally acceptable." The carrier will typically be aqueous, and may include a thickening agent, such as high molecular weight carboxyvinyl polymers (e.g., CARB0P0L®, " available from B. F. Goodrich Chemical Co.); various celluloses known for such use in the art

(e.g., cellulose, hydroxyethylcellulose, and methoxy cellulose); poly¬ ethylene glycol with a molecular weight distribution of about 400 to about 4,000; low molecular weight hydroxyethylmethacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polysaccharide gums (e.g., xanthan gum) and mixtures thereof.

The compositions of the present invention must be formulated in a manner such that the particulate abrasive material remains in suspen¬ sion, or goes into suspension easily upon mild agitation (i.e., shaking) of the compositions. Various methods of formulation may be utilized to P achieve this suspension, including providing the compositions with a viscosity or density sufficient to keep the particulate material in suspension, and/or using an antistatic agent to prevent electrostatic agglomeration of the particulate material and facilitate its suspension in the compositions.

The compositions may optionally further comprise one or more surfactants, preservatives, chelating agents, tonicity agents or anti¬ static agents. These types of ingredients are well known in the art. An exhaustive listing of illustrative examples of these ingredients is therefore believed to be both unnecessary and inappropriate. Repre- sentative examples of these types of ingredients include: surfactants such as polyoxyethylene/polyoxypropylene copolymers (e.g., PLUR0NIC 127); preservatives such as thimerosal, sorbic acid, P0LYQUAD® (i.e., a polymeric germicide also known as 0NAMER M, available from Onyx Chemical Co.), and benzalkoniu chloride; chelating agents such as EDTA; tonicity agents such as sodium chloride and potassium chloride; and antistatic agents such as Foraperle B320 (available from Rilsan Corporation). In addition to the for ulatory function mentioned in the preceding para ¬ graph, antistatic agents may also be useful to prevent electrostatic binding of abrasive materials to the surface of some types of contact lenses.

As mentioned above, a preferred embodiment of the present invention utilizes a packaging arrangement wherein the enzyme component of the compositions is not combined with the remaining components of the com-

positions until time of use. This arrangement avoids the necessity for -long-term shelf-life stability. The compositions packaged in this manner are particularly preferred for professional use by an eye care specialist, such as an ophthalmologist, optometrist, optician or trained technician. A composition packaged in this manner can be conveniently prepared for use by merely combining the enzyme with the remaining components of the composition and mixing the combined components by means of agitation (i.e., shaking and/or stirring). The type of packaging utilized is not critical, so long as the packaging is suitable for pharmaceutical use. The use of a sealed foil packet for the enzyme component and a sealed plastic bottle for the remaining components of the composition represents a preferred packaging arrangement. With this arrangement, the enzyme is simply removed from the packet, added to the container, and mixed with the contents of the container to provide a contact lens cleaning composition according to the present invention. Depending on the precise nature of the formulation, this composition would be useful for either a single, immediate use or many uses extending over several days.

The present invention also concerns a method of cleaning contact lenses utilizing the above-described compositions. This method com¬ prises applying a small amount of the composition (e.g., a few drops if in liquid form) to the surfaces of the lens and rubbing the composition over the surfaces of the lens for a short time, normally for 30 seconds or less. The thus cleaned lens is then rinsed with a suitable contact lens rinsing solution (e.g., saline solution) to remove the cleaning composition and debris from the surface of the lens. The lens will normally be completely cleaned at this point. Prior to reinsertion in the eye, the cleaned lens will normally be disinfected using various known disinfection methods, such as soaking in a disinfectant solution containing one or more germicides.

The mechanism which enables the compositions of the present invention to clean contact lenses completely and rapidly is not totally understood. However, it is clear that the remarkable results achieved with these compositions are attributable to a positive interaction

between the enzyme and abrasive components of the compositions. Prior art compositions containing enzymes have generally been capable of com¬ pletely cleaning lenses, but have typically required an extended soaking period of 15 minutes or more to achieve this cleaning. Prior art com- positions containing an abrasive material have generally had the advan¬ tage of working very rapidly (i.e., in roughly one minute or less); however, the degree of cleaning achieved with these compositions has not been as complete as the cleaning achieved with enzyme-containing com¬ positions. The prior art abrasive compositions have generally been very effective in removing large deposits from the surfaces of contact lenses, but have been less effective in removing minute deposits from the lens surface and have generally not been effective in removing deposits located beneath the surface of the lens in the pores or inter¬ stices of the lens. The compositions of the present invention have demonstrated a very surprising ability to clean soiled contact lenses both very rapidly and completely. The degree of cleaning achieved with the present compositions is much better than that achieved with prior art abrasive compositions, and the rapidity of cleaning is comparable or in some cases superior to that of prior art abrasive compositions.

EXAMPLE 1

This example further illustrates the formulation of compositions according to the present invention.

Concentration (Wt. %)

Composition

Ingredient B

French Naturelle ES 10.0 10.0 10.0

Pancreatin 6X 2.5 5.0 10.0

Sodium Chloride 0.6 0.6 0.6

Boric Acid 0.2 0.2 0.2

Edetate Disodium 0.1 0.1 0.1

POLYQUAD® 0.01 0.01 0.01

Tween 21 0.5 0.5 0.5

Hydroxyethy1cellu1ose 0.8 0.8 0.8

Sodium 8orate (Decahydrate) 0.25 0.25 0.25

Sodium Hydroxide 0.037 0.037 0.037

HCl/NaOH QS pH 7 QS pH 7 QS pH 7

Purified Water QS 100 mL QS 100 mL QS 100 mL

These compositions may be prepared as follows. The tween 21 is added to a portion of the purified water and dissolved. The hydroxyethy!cellu¬ lose is then slowly added to the resulting solution with stirring until completely wetted and dispersed. A second solution is then prepared by dissolving the sodium chloride, boric acid, and edetate disodium in a second portion of the purified water. The sodium borate is then added to this second solution and dissolved, and the POLYQUAD® is added and dissolved following addition of the sodium borate. The second solution is then added to the first solution, and the French Naturelle ES (Nylon 11 particles, available from Rilsan Corporation) is slowly added to the resulting solution with stirring. The Pancreatin 6X is then dissolved in this solution. The remainder of the purified water is then added to bring the final volume of the solution to approximately 100 mL, and a small amount of HC1 and/or NaOH is added to bring the pH of the solution to 7.

EXAMPLE 2

This example demonstrates the efficacy of the present compositions in cleaning soiled contact lenses.

PART I

A total of 37 clean contact lenses were treated with a solution of the following formula to simulate the deposits typically found on human worn contact lenses.

Deposition Model Solution

Ingredient Concentration (Wt. %)

Lysozyme 0.05 Mucin 0.05

Sodium Chloride 0.9 Distilled Water QS 500 mL NaOH/HCl QS pH 7.0

Each of the lenses was placed in a vial containing 5 L of this solution and heated for one hour at 92°C. The lenses were then removed from the containers and rinsed with saline to remove excess debris from the sur- faces of the lens. The rinsed lenses were then again placed in vials and 5 L of the deposition model solution (fresh) was added. The lenses were then again heated at 92°C for one hour. Following this second heating cycle, the lenses were removed from the vials and washed with saline to remove excess debris. The rinsed lenses were then stored in saline.

PART II

Four contact lens cleaning compositions identical to the compositions described in Example 1 except for variations in the concen¬ tration of enzyme utilized were prepared. These compositions contained the following concentrations of pancreatin 6X:

Composition Enzyme (Pancreatin 6X) Concentration

A 1.0%

B 2.0%

C 5.0% D 10.0%

The deposits on the lenses treated with the deposition model solution were then rated, based on the Rudko Lens Deposit Classification System. The criteria for this rating system are reproduced below.

Rudko Lens Deposit Cl ssification System

Classification Heaviness of Deposit

I Clean

II Visible under oblique light when wet or dry using 7X magnification

III Visible when dry with the unaided eye IV Visible when wet with the unaided eye

Extent of Deposit a 0%-25% of lens b 25%-50% of lens c 50%-75% of lens d 75%- 100% of lens

Type of Deposit

C Crystalline

G Granular

F Filmy

The lenses were then individually treated with one of the above compositions as follows. The lens to be cleaned was held in the palm of the hand and two drops of the cleaning composition were placed on each

side of the lens. The lens was then rubbed with a finger while remain¬ ing in the palm of the hand for approximately 20 seconds. The lens was then turned over and the opposite side thereof was rubbed in the same manner for approximately 20 seconds. The lens was then rinsed with saline to remove the cleaning composition and debris removed from the lens surfaces by the composition. The thus cleaned lenses were then examined and assigned a Rudko rating. Lenses which had not been com¬ pletely cleaned (i.e., rating below I) were subjected to a second clean¬ ing cycle, and were then re-examined and rated. The results of these experiments are set forth in the Table 1 below.

Table 1

Cleaninq Efficacy Using Laboratory Deposited Lenses

Initial Rating After Cleaninq

Composition Lens Type Rating 1st 2nd

A Hydrocurve II IIIFd IIFa I

Hydrocurve II IIFc I -

Bausch & Lomb IIIFd IIFc IIFc

Bausch & Lomb IIIFa IIFa IIFa

Tresoft IIIFd IIIFb I

Tresoft IIIFc IIIFb I

Tresoft IIIFd IIFa I

Tresoft IIIFb IIFa I

B Hydrocurve II IIIFc I -

Hydrocurve II IIIFd I -

Bausch & Lomb IIIFd IIFd IIFd

Bausch & Lomb IIIFc IIFa IIFa

Tresoft IIIFd IIIFc I

Tresoft IIIFc IIIFb I

Tresoft IIIFd I I

Tresoft IIIFb I I

C Hydrocurve II IIIFc I -

Hydrocurve II IIIFd I -

Bausch & Lomb IIIFd IIIFa IIFa

Bausch & Lomb IIIFc I -

Tresoft IIIFd IIFb I

Tresoft IIIFd IIFa I

Tresoft IIIFc I -

Tresoft IIIFb I —

1 Continiled . . .

Table 1 - Continued

Initial Rating After Cleaninq

Composition Lens Type Rating 1st 2nd

D Hydrocurve II IIIFc I _

Hydrocurve II IIIFd I -

Bausch & Lomb IIIFd IIFa I

Bausch & Lomb IIIFd IIFa I

Tresoft IIIFd IIFa I

Tresoft IIIFd IIFa I

OPTI-CLEAN II®* Hydrocurve II IIIFa IIFa I

Bausch & Lomb IIFa I -

Bausch & Lomb IIIFd IIIFb IIIFa

Tresoft . IIIFd IIFa IIFa

Tresoft IIIFd IIIFc IIIFb

Tresoft IIFa I -

Tresoft IIIFd IIIFc IIIFa

*This commercially available product (available from Alcon Laboratories, Inc.) has the same formula as the composition illustrated in Example 1, except for Pancreatin 6X, which is not present in this product.

EXAMPLE 3 "

This example further demonstrates the efficacy of the present compositions in cleaning contact lenses.

A total of 20 contact lenses which had been soiled as the result of normal human wear were examined and assigned a Rudko rating. The lenses were then treated with the same compositions described in Example 2 above, using the procedures described in Part II of Example 2. The lenses were then examined and assigned a Rudko rating. Lenses which had not been completely cleaned (i.e., rating below I) were subjected to a second cleaning cycle, and were then re-examined and rated. The results of these experiments are set forth in Table 2 below.

Table 2

Cleaninq Efficacy Using Human Worn Lenses

Initial Rating After Cleaninq

Composition Lens Type Rating 1st 2nd

Hydromarc IIId IIIFb I Unknown IIIFc IIFc IIF Tresoft IIFb I Tresoft IVFd IVFd IVFb

Scanlens IVFd IVFd IVFc Tresoft IIFb I Tresoft IIIFd IIFb IIFa Tresoft IIIFc IIIFa I

Durasoft IIIFb IIFa IIFa Tresoft IVFd IIFa I Tresoft IIFb I Tresoft IIIFd I

Unknown IIFd IIFa Unknown IIFc IIFa Tresoft IVFd I Tresoft IIIFd I

OPTI-CLEAN II® Scanlens IVFd IVFd IVFd Tresoft IIFd IIFa I Tresoft IIFb IIFa IIFa Tresoft IIIFc IIFb IIFa