GB1601430A - Method of treating contact lenses - Google Patents
Method of treating contact lenses Download PDFInfo
- Publication number
- GB1601430A GB1601430A GB2132178A GB2132178A GB1601430A GB 1601430 A GB1601430 A GB 1601430A GB 2132178 A GB2132178 A GB 2132178A GB 2132178 A GB2132178 A GB 2132178A GB 1601430 A GB1601430 A GB 1601430A
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- GB
- United Kingdom
- Prior art keywords
- yellow
- clear
- solution
- treating
- lenses
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L12/00—Methods or apparatus for disinfecting or sterilising contact lenses; Accessories therefor
- A61L12/08—Methods or apparatus for disinfecting or sterilising contact lenses; Accessories therefor using chemical substances
- A61L12/12—Non-macromolecular oxygen-containing compounds, e.g. hydrogen peroxide or ozone
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- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Epidemiology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Eyeglasses (AREA)
Description
(54) A METHOD OF TREATING CONTACT LENSES
(71) We, CONTACT LENSES MANUFACTURING LIMITED, a British Limited
Company, of 14 - 16 Child's Place, London SW5 9RX, do hereby declare the invention for which we pray that a Patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement:
This invention relates to a method for treating contact lenses and more particularly but not exclusively for cleaning soft contact lenses.
Contact lenses are becoming ever more popular, because of their convenience and because they enable spectacles to be dispensed with. In particular, the use of soft contact lenses, which are much more easily accommodated within the eye, is becoming prevalent, with the development of improved materials.
Hard contact lenses may be made of glass or a plastics material such as polymethyl methacrylate resin (e.g. as sold under the Registered Trade Mark PERSPEX).
Soft contact lenses are generally made from hydrophilic polymeric- material, generally incorporating hydroxyalkyl methacrylates. Soft lenses are commercially available inter alia under the Registered Trade Marks HYDRON and HYDROFLEX. Superior types of soft lenses are made in accordance with British Patent No. 1391438 or 1439132 from polymerized mixtures of hydrophilic olefinically unsaturated monomers and hydrophobic olefinically unsaturated monomers. Such lenses are commercially available under the
Registered Trade Mark SAUFLON.
Contact lenses, and in particular soft contact lenses, do however have certain disadvantages which are peculiar to them and which raise problems that have not hitherto been solved satisfactorily.
Firstly, contact lenses suffer from surface contamination in use and from deposition onto the lenses of solid substances such as metabolites from the tear solutions of the eyes of the wearer.
Secondly, soft contact lenses have a tendency to discolour, e.g. to turn brown with prolonged use. The daily sterilization of soft lenses by boiling in aqueous saline solution greatly accelerates the rate of discolouration of the lenses so treated. Known cleaning solutions employ powerful oxidising agents and are quite unsuitable for use by a lay wearer of contact lenses. In fact such solutions are suitable only for use by trained medical and ophthamological staff. Additionally, the treatment of contact lenses by the robust methods generally in use at the present time may cause unacceptable alterations in the parameters of the lenses, e.g., variations in diameter, power and radius. Clearly such variations in prescription will not be tolerable and should be avoided.
It is an object of the present invention to provide a method for treating contact lenses which is suitable for use by a contact lens wearer and which will prevent, remove or help to alleviate such contamination and/or discolouration, with little or no significant variations in the lenses treated thereby.
According to the present invention, there is provided a method of treating a contact lens which is suitable for performance by the wearer of the contact lens, which method comprises periodically contacting the contact lens with a treating solution comprising a pharmacologically acceptable aqueous buffered solution of a reducing agent.
It is to be understood that the term "periodically" is to be widely interpreted and includes within its scope, for example, treatments at daily or more frequent than daily intervals and treatments at monthly, six-monthly or even annual intervals.
Suitable examples of reducing agents which may be employed in the present invention are water-soluble metabisulphites, nitrites and sulphites, in particular the alkali metal, e.g.
sodium, salts thereof.
The concentration of the reducing agent in the treating solution is suitably from 0.03% to 5%, preferably about 1%, by weight of the solution.
Very preferably the solution also contains a chelating agent and the particular chelating agent may be selected in accordance with the pH that the solution is to have. Examples of such chelating agents are diethylene triamine pentaacetic acid (pentasodium salt) (DPTA) and ethylene diamine tetraacetic acid (EDTA) which are useful respectively for alkaline and acidic treating solutions.
Additionally, it has been found desirable that the solution should contain a surfactant, and water-soluble ethylene oxide/propylene oxide block co-polymers have proved particularly effective.
It will be understood that the components of the treating solution for use in this invention may be in solid form for dissolution in an aqueous medium to form a pharmacologically acceptable solution as defined hereinbefore. It is to be understood that the term "solid" employed herein is intended to embrace solid matter whether in bulk form, e.g. tablet, or in particulate form.
In certain circumstances it has been found that the pH of the treating solution is relevant to the effectiveness of the treating solution. From a pharmacological point of view the solutions preferably have a pH of 7 + 1.
An Example of a formulation of a treating solution for use in the present invention and of its efficacy upon contact lenses of various compositions will now be described by reference to the following experimental data.
Experiments were performed upon soft contact lenses of various compositions and parameters in order to determine the effectiveness of the present invention and the changes in parameters, if any, of contact lenses treated thereby.
The parameters of fifty contact lenses made for hydrophilic copolymer derived from both hydrophobic and hydrophilic olefinically unsaturated monomers were measured, the lenses washed in a commercially available cleaning fluid sold under the Registered Trade Mark
MONOCLENS, then rinsed twice in saline solution before being autoclaved under a saline solution. To accelerate the deterioration of the lenses refluxing was effected for 100 hours upon batches of ten lenses in 100ml of a buffered saline solution, available under the
Registered Trade Mark SALETTE.
The condition of the lenses and of the refluxing solution was monitored over the refluxing period and the parameter and conditions thereof are as shown in Tables 1 to 5 hereinafter, in which in the descriptions of the lenses the percentage indicated is a measure of the water absorption of the lens after immersion thereof in dry state into distilled water (pH 6.5) calculated as follows: % water absorbed =
where WO is the weight of the lens before immersion and W1, its weight after immersion for a specified number of days. Also in the description of the lenses "chemical" indicates that polymerization of the lens material has been chemically effected whereas "physical" indicates that polymerization has been effected by y-irradiation. Such contact lenses are commercially available under the Registered Trade Mark SAUFLON.
TABLE 1 "85% Physical
No. Radius Power Diameter Comments 1 7.8 -1.00 14.00 2 8.4 -0.25 14.30 3 7.8 Afocal 14.00 After 25 hours it appeared that lenses had turned yellow 4 8.1 Afocal 14.00 7 8.4 Afocal 14.30 After 49 hours same appearance as after 25 hours 8 8.1 -0.12 14.00 9 8.4 +0.12 14.00 After 73 hours same appearance as after 49 hours 10 8.1 Afocal 14.00 11 8.1 Afocal 14.00 After 92 hours lenses slightly more yellow 12 8.4 Afocal 14.50
Ref 13 18 -0.12 14.30 FINAL COMMENTS: refluxed for 100 hours. VERY YELLOW TABLE 2 "85% Chemical"
No.Radius Power Diameter Comments 14 7.8 - 7.25 13.00 15 7.8 - 9.00 13.00 16 8.1 - 8.50 13.00 After 25 Hours no apparent change 17 8.1 - 1.50 13.00 18 7.8 + 0.75 13.00 After 49 hours no apparent change 19 7.8 - 8.00 13.00 20 7.8 -10.00 13.00 After 73 hours no apparent change 21 8.4 - 1.25 13.00 22 7.8 - 1.00 13.00 After 97 hours no apparent change 23 7.8 + 0.75 13.00
Ref 24 7.8 + 0.75 13.00 FINAL COMMENTS: Refluxed for 100 hours, yellow against light.
TABLE 3 "70% Chemical"
No. Radius Power Diameter Comments 26 8.8 -7.25 12.60 27 8.8 -7.62 12.60 28 8.8 -7.75 12.75 After 25 hours some tendency for lens cloudiness 29 8.8 -7.37 12.75 30 8.8 -7.62 12.65 After 49 hours condition as after 25 hours 31 8.8 -7.75 12.60 32 8.8 -7.00 12.60 After 73 hours still no change from 25 hours state 33 8.8 -6.50 12.60 34 8.8 -6.87 12.75 After 97 hours no change from 73 hours state 35 8.8 -7.87 12.60
Ref 36 8.4 -5.00 13.30 FINAL COMMENTS: Refluxed for 100 hours. Yellowing and cloudiness observed TABLE 4 "70% Chemical"
No.Radius Power Diameter Comments 37 8.8 -8.37 12.75 38 8.8 -8.50 12.80 39 8.8 -8.50 12.75 After 25 hours solution turned slightly cloudy 40 8.8 -8.25 12.75 41 8.8 -8.57 12.75 After 49 hours solution slightly cloudy and lenses extremely cloudy 42 8.8 -8.12 12.75 (not yellow) 43 8.8 -8.12 12.80 After 73 hours solution still cloudy. Only one lens very cloudy.
44 8.8 -8.25 12.65 Two others slightly yellow. The rest are back to transparence as before refluxing 45 8.8 -8.25 12.75 After 97 hours no change from 73 hours solution except that no 46 8.8 -8.50 12.75 apparent yellow lenses just one cloud lens
Ref 47 8.4 -5.25 13.50 FINAL COMMENTS. Refluxing for 100 hours; yellow against light; 1 lens cloudy.
TABLE 5 "70% Physcial (Different Formulation from that of Table 4)
No. Radius Power Diameter Comments 48 8.4 -4.75 13.00 49 8.2 -5.75 13.00 50 8.2 -6.50 13.70 After 25 hours lenses turned slightly yellow 51 8.8 -4.50 12.00 52 8.4 -2.50 12.00 After 49 hours yellow colour disappeared back to transparance as 53 8.4 -2.50 12.00 before refluxing 54 8.4 -6.50 13.70 After 73 hours All lenses transparent and clear with the exception 55 8.4 -4.00 13.00 of one that had turned extremely cloudy.
56 8.6 -4.00 12.30 After 97 hours 4 cloudy lenses; the rest as at 73 hours 57 8.2 -4.50 13.00
Ref 58 8.6 -2.75 13.00 FINAL COMMENTS: Refluxing for 100 hours. Yellow against light, 4 cloudy It will be observed from Tables 1 to 5 that the effect of the refluxing was to cause yellowing and/or clouding of the lenses so treated. These lenses were then treated batchwise in the following solution:
Exemplary solution
Sodium Metabisulphite 10 grams
EDTA 20 grams
Polyoxethylene-Polyoxypropylene
Copolymer 10 grams
Sodium Phosphate 8 grams
Sodium Chloride 9 grams
Purified Water to 1000 grams
In each case the treatment involved placing a lens in 8ml of the treating solution and leaving it therein at room temperature for 24 hours, followed by removal from the solution, rinsing and boiling twice in normal saline solution.
It will be observed that Solution A was effective in 10 out of 19 instances.
The results of the treatments were as follows: TABLE 6 i) With Solution A.
Before Treatment After Treatment
Physical 85%
Condition Condition Remarks 1 yellow yellow No cleaning effect 2 yellow yellow No Cleaning effect 3 brown yellow No Cleaning effect 4 yellow yellow No Cleaning effect
Chemical 85% 1 yellow clear Lens clean 2 yellow clear Lens clean 3 yellow slightly yellow Some effect during cleaning 4 yellow, black, speck on lens yellow, black mark No cleaning effect.Black spot still present
Chemical 70% 1 yellow slightly yellow Some cleaning effect 2 yellow clear Clear 3 yellow clear Clear 4 yellow slightlt yellow Some cleaning effect TABLE 6 (cont'd)
Before Treatment After Treatment
Physical 70%
Condition Condition Remarks
Chemical 70% 1 yellow yellow No cleaning effect 2 yellow yellow No cleaning effect 3 yellow yellow slightly yellow Some cleaning effect 4 yellow yellow Slightly yellow Some cleaning effect
Physical 70% 1 yellow clear Clean 2 yellow yellow No cleaning effect 3 yellow yellow No cleaning effect In further experiments to establish the effectiveness of the method of the present invention, lens solution A as previously described was again employed.
The parameters and conditions of a large number of "70% physical" and/or "85So physical" were ascertained and then the lenses were individually immersed in 6 mls of a respective solution and left to stand at room temperature for a period of seven days respectively. The results obtained were as follows.
TABLE 7
Solution A for Seven Days: 70% Physical
Before Treatment After Treatment
Condition Condition
1 Yellow 1 Clear
2 Yellow 2 Clear
3 Yellow 3 Clear
4 Brown 4 Yellow
5 Yellow 5 Clear
6 Brown 6 Yellow
7 Cloudy 7 Yellow
8 Brown 8 Yellow
9 Yellow 9 Yellow
10 Yellow 10 Yellow
11 Yellow 11 Clear
12 Brown 12 Yellow
13 Yellow 13 Clear
14 Brown 14 Brown
15 Yellow 15 Clear
16 Yellow 16 Clear
17 Yellow 17 Yellow
18 Yellow 18 Clear
19 Yellow 19 Yellow
20 Yellow 20 Yellow
21 Yellow 21 Clear
22 Yellow 22 Clear
23 Yellow 23 Clear
24 Yellow 24 Yellow
25 Yellow 25 Clear
Within statistical limits the parameters of the lenses in Table 7 were substantially unchanged after the end of the test.This is most satisfactory particularly in view of the fact that the test (i.e., immersion for seven days) is a severe one and much more taxing than would be the case in normal use (e.g., 8 hours immersion per week).
From the foregoing experimental results it will be seen that the method of the present invention is capable of removing deposits and/or discolouration from contact lenses. The method of this invention are particularly suitable for treating soft contact lenses made in accordance with British Patent No. 1,391,438 or 1,439,132 available under the Registered
Trade Mark SAUFLON.
As indicated hereinbefore, previous solutions for treating contact lenses have employed oxidising agents. It is therefore quite unexpected that the method of the present invention should prove efficacious in the way that has been described.
WHAT WE CLAIM IS:
1. A method of treating a contact lens which is suitable for performance by the wearer of the contact lens, which method comprises periodically contacting the contact lens with a treating solution which comprises a pharmacologically acceptable aqueous buffered solution of a reducing agent.
2. A method according to claim 1, wherein the reducing agent comprises a metabisulphite.
3. A method according to claim 1 or 2, wherein the reducing agent comprises a sulphite.
4. A method according to any one the preceding claims, wherein the reducing agent comprises a nitrite.
5. A method according to any one of claims 2 to 4, wherein the reducing agent is used in
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (17)
1 Yellow 1 Clear
2 Yellow 2 Clear
3 Yellow 3 Clear
4 Brown 4 Yellow
5 Yellow 5 Clear
6 Brown 6 Yellow
7 Cloudy 7 Yellow
8 Brown 8 Yellow
9 Yellow 9 Yellow
10 Yellow 10 Yellow
11 Yellow 11 Clear
12 Brown 12 Yellow
13 Yellow 13 Clear
14 Brown 14 Brown
15 Yellow 15 Clear
16 Yellow 16 Clear
17. A treating solution for use in a method as claimed in claim 12, substantially as hereinbefore described with reference to the Example.
17 Yellow 17 Yellow
18 Yellow 18 Clear
19 Yellow 19 Yellow
20 Yellow 20 Yellow
21 Yellow 21 Clear
22 Yellow 22 Clear
23 Yellow 23 Clear
24 Yellow 24 Yellow
25 Yellow 25 Clear
Within statistical limits the parameters of the lenses in Table 7 were substantially unchanged after the end of the test.This is most satisfactory particularly in view of the fact that the test (i.e., immersion for seven days) is a severe one and much more taxing than would be the case in normal use (e.g., 8 hours immersion per week).
From the foregoing experimental results it will be seen that the method of the present invention is capable of removing deposits and/or discolouration from contact lenses. The method of this invention are particularly suitable for treating soft contact lenses made in accordance with British Patent No. 1,391,438 or 1,439,132 available under the Registered
Trade Mark SAUFLON.
As indicated hereinbefore, previous solutions for treating contact lenses have employed oxidising agents. It is therefore quite unexpected that the method of the present invention should prove efficacious in the way that has been described.
WHAT WE CLAIM IS:
1. A method of treating a contact lens which is suitable for performance by the wearer of the contact lens, which method comprises periodically contacting the contact lens with a treating solution which comprises a pharmacologically acceptable aqueous buffered solution of a reducing agent.
2. A method according to claim 1, wherein the reducing agent comprises a metabisulphite.
3. A method according to claim 1 or 2, wherein the reducing agent comprises a sulphite.
4. A method according to any one the preceding claims, wherein the reducing agent comprises a nitrite.
5. A method according to any one of claims 2 to 4, wherein the reducing agent is used in
the form of a sodium salt thereof.
6. A method according to any preceding claim, wherein the concentration of the reducing agent is from 0.03% to 5% by weight of the solution.
7. A method according to any preceding claim, wherein the treating solution further contains a chelating agent.
8. A method according to claim 7, wherein the chelating agent comprises ethylene diamine tetraacetic acid or an alkali metal salt thereof.
9. A method according to claim 7, wherein the chelating agent comprises diethylene triamine pentaacetic acid or an alkali metal salt thereof.
10. A method according to any preceding claim, wherein the treating solution further comprises a surfactant.
11. A method according to claim 10, wherein the surfactant comprises a water-soluble ethylene oxide-propylene oxide block co-polymer.
12. A method according to any preceding claim, wherein the treating solution has a pH of from 6 to 8.
13. A method of treating contact lens, substantially as hereinbefore described with reference to the foregoing Example or any individual test thereof.
14. A contact lens when treated by a method as claimed in any one of claims 1 to 13.
15. A contact lens according to claim 14, which is made of a soft polymeric material.
16. A contact lens according to claim 15, wherein the polymeric is at least partially derived from hydroxyethyl methacrylate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2132178A GB1601430A (en) | 1978-05-23 | 1978-05-23 | Method of treating contact lenses |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2132178A GB1601430A (en) | 1978-05-23 | 1978-05-23 | Method of treating contact lenses |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1601430A true GB1601430A (en) | 1981-10-28 |
Family
ID=10160908
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2132178A Expired GB1601430A (en) | 1978-05-23 | 1978-05-23 | Method of treating contact lenses |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1601430A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0139994A1 (en) * | 1983-08-25 | 1985-05-08 | Allergan, Inc. | Process and kit for disinfection of contact lenses |
| EP0142642A1 (en) * | 1983-08-25 | 1985-05-29 | Barnes-Hind, Inc. | Process and kit for sodium sulfite neutralization of H2O2 in contact lenses |
| GB2189045A (en) * | 1986-03-22 | 1987-10-14 | Smith & Nephew Ass | Disinfecting contact lenses using sulphur dioxide and/or benzoic acid |
| EP0242998A2 (en) * | 1986-03-22 | 1987-10-28 | SMITH & NEPHEW plc | Disinfecting composition |
| JPS62270913A (en) * | 1986-03-22 | 1987-11-25 | スミス アンド ネフユ− アソシエ−テツド カンパニ−ズ ピ−エルシ− | Solution and method for sterilizing contact lens |
| US4738790A (en) * | 1984-08-21 | 1988-04-19 | Toyo Contact Lens Co., Ltd. | Method for cleaning contact lenses with composition containing amidoamine surfactant, thiourea and reducing agent |
-
1978
- 1978-05-23 GB GB2132178A patent/GB1601430A/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0139994A1 (en) * | 1983-08-25 | 1985-05-08 | Allergan, Inc. | Process and kit for disinfection of contact lenses |
| EP0142642A1 (en) * | 1983-08-25 | 1985-05-29 | Barnes-Hind, Inc. | Process and kit for sodium sulfite neutralization of H2O2 in contact lenses |
| US4738790A (en) * | 1984-08-21 | 1988-04-19 | Toyo Contact Lens Co., Ltd. | Method for cleaning contact lenses with composition containing amidoamine surfactant, thiourea and reducing agent |
| GB2189045A (en) * | 1986-03-22 | 1987-10-14 | Smith & Nephew Ass | Disinfecting contact lenses using sulphur dioxide and/or benzoic acid |
| EP0242998A2 (en) * | 1986-03-22 | 1987-10-28 | SMITH & NEPHEW plc | Disinfecting composition |
| JPS62270913A (en) * | 1986-03-22 | 1987-11-25 | スミス アンド ネフユ− アソシエ−テツド カンパニ−ズ ピ−エルシ− | Solution and method for sterilizing contact lens |
| EP0242998A3 (en) * | 1986-03-22 | 1988-07-06 | Smith And Nephew Associated Companies P.L.C. | Disinfecting composition |
| GB2189045B (en) * | 1986-03-22 | 1990-11-28 | Smith & Nephew Ass | Disinfecting contact lenses using sulphur dioxide. |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |