Compositions – Electrolytes for electrical devices
Patent
1986-12-09
1989-09-05
Niebling, John F.
Compositions
Electrolytes for electrical devices
252105, 2524081, 2521863, 422 28, 422 29, 422119, A61L 218, G02C 1300, A01N 5900
Patent
active
048636274
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to the cleaning and/or disinfection of contact lenses and has particular, but not exclusive, application to the cleaning and disinfection of hydrophilic soft contact lenses, for daily and particularly extended wear. Methods and compositions provided by the invention may also be applied to hard contact lenses. It provides disinfecting compositions typically also having a cleansing action and methods of disinfecting contact lenses.
Contact lenses are thin convex lenses placed directly on the eye surface to correct sight defects. There are two general categories of contact lenses, namely hard lenses and soft lenses. Hard lenses are made of glass or, more usually, hard plastics, especially cross-linked polymethylmethacrylate. Soft lenses may be made of hydrophobic plastics, especially cross-linked dimethylpolysiloxane, but usually are made of hydrophilic plastics, especially polyhydroxyethylmethacrylate cross-linked with hydroxyethyldimethacry-late.
The disinfection of hydrophilic soft lenses using chemical agents presents a particular problem in that the lenses can absorb chemical agents from disinfecting solutions in which they are soaked. The most commonly used disinfecting solutions for soft contact lenses are aqueous solutions containing chlorhexidine (or a salt thereof) and it is well established that a sufficiently high concentration of chlorhexidine can build up in the lenses to cause irritation and, some times, damage to the eye of the lens wearer.
Extended wear lenses may contain a higher content of carboxyl groups than other soft contact lenses generally. These groups tend to bind chlorhexidine particularly strongly increasing the tendency for these lenses to build up a high concentration of chlorhexidine. To avoid the use of chlorhexidine for disinfection of such lenses, it has been proposed to use hydrogen peroxide as soaking solution for the lenses. Hydrogen peroxide is an efficient disinfectant and is particularly attractive in that its decomposition product is simply water. However, hydrogen peroxide is such a vigorous oxidising agent that it is imperative that it be thoroughly removed from the lenses before they are reinserted in the eye. Failure to do this would be likely to result in severe discomfort and possible damage to the eye.
It has been proposed to remove hydrogen peroxide from lenses which have been soaked in a solution of it by removing the lenses from the solution, placing them in a second container including a disk bearing platinum black bound thereon and adding water, or a solution of salts, buffers and preservatives. The platinum black decomposes any residual hydrogen peroxide.
The disadvantages of this process include (a) the necessity of removing the lenses from the hydrogen peroxide solution (which will be effectively sterile because of the presence of the hydrogen peroxide) to a second container which may not be sterile and may indeed contain significant contamination and (b) the danger that the neutralisation step might inadvertently be omitted by a user on some occasion leading to discomfort or eye damage. The danger of significant contamination occurring in the second container is particularly severe with extended wear lenses because of the lengthy periods of time during which the lenses are worn continuously and the disinfection apparatus is unused. The water or solutions used in the second container are also a potential source of contamination.
Other disinfection/cleansing procedures based on peroxides have been proposed. These also suffer from various disadvantages.
Thus French Patent Application 2400906 describes a composition for cleaning contact lenses containing an ene diol and a peroxide which are simultaneously added to the lens. The ene diol is intended to reduce the hydrogen peroxide over a period after disinfection has taken place. However, the presence of the ene diol at the outset of the cleansing procedure means that there is a risk of the peroxide being inactivated before cleansing and disinfection are complete. Also, as both
REFERENCES:
patent: 3154494 (1964-10-01), Speak
patent: 3243377 (1966-03-01), Stolar
patent: 3843557 (1974-10-01), Fanger
patent: 3867101 (1975-02-01), Herring
patent: 4016089 (1977-04-01), Regan
patent: 4115293 (1978-09-01), Schoenholz
patent: 4295985 (1981-10-01), Petrow
patent: 4568517 (1986-02-01), Kaspar
patent: 4668475 (1987-05-01), Meloy
patent: 4670178 (1987-06-01), Huth
Am. J. Optom. & Physiol. Optics, Chun et al, 64, 274-276, Apr. 1987.
JAMA, Stehr-Green, 258, 57-60, Jul. 3, 1987.
Davies David J. G.
Meakin Brian J.
Rees John E.
Staniforth John N.
Niebling John F.
Rodriguez I.
University of Bath
LandOfFree
Cleaning and/or disinfection of contact lenses does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cleaning and/or disinfection of contact lenses, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cleaning and/or disinfection of contact lenses will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-241757