Process for the preservation and cleaning of hydrophilic lenses

Details Process for the preservation and cleaning of hydrophilic lenses Process for the preservation and cleaning of hydrophilic lenses

1985-09-06

1989-05-30

Pal, Asok

Cleaning and liquid contact with solids

Processes

Including forming a solidified or hardened coating for cleaning

134 17, 134 42, 422 28, B08B 310

Patent

active

048348040

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention relates to the preservation and cleaning of lenses in general and, more particularly to a process for the preservation and cleaning of hydrophilic lenses by means of the freezing in hypertonic solution of sodium chloride or another substance that modifies the cryoscopic solution degree.


BACKGROUND OF THE INVENTION

As known in the field with which the present invention is related to, one of the topics of greatest controversy in contactology is undoubtedly the theme related to the preservation of hydrophilic lenses.
As known, there are two available processes for the treatment of hydrophilic lenses, i. e., the chemical and the thermal.
Asepsis and preservation chemical process uses basically thimerosalt and, as a preservative, the chloroxedine. The advantages relative to this process are related to its efficiency as an antisseptic and to its handling facility. The high cost of the products, however, the development of hypersensitiveness processes with consequent intolerance to the use of lenses and the greatest facility of inorganic impregnation with, for instance, mercury and calcium salts, arise as negative factors limiting its utilization.
Three different stages may be outstanding in this process, thus included: lenses cleaning after use, with an available product, for example, PLIAGEL; preservation with products based on thimerosalt and chloroxedine; disproteinization periodically, with the purpose of making the proteins lysine, having as active agent, the papain. Among the three stages, the disproteinization may be considered the one that presents the best results, inside what it proposes.
However, the thermic process is constituted by two different technics, which are: The hot (by boiling) and the cold (by freezing).
The preservation process by heat is the most used and consists on the direct boiling or in water-bath, in a saline solution or distilled water. Apparently, boiling only presents the advantage of making calcium salts, in the form of carbonate, more soluble, which make difficult its impregnation and difficultates lipids deposition. This process, however, sins by the great risk of damn made to the lenses when realized under direct boiling in a common oven, what does not occur with electric aseptizers. Boiling also promotes the protein cooking, making them more agglutinated and adherent to the villosities of lens surface. We may cite as an example the phenomenon occurring with the white of the egg, basically constituted by albumine, a protein that predominates in the human tear, which on being subjected to cooking, gets firm and opaque, therefore different enough from its initial state. In the case of lenses, proteins also have these transformations and are therefore much more adherent and difficult to be removed when exposed to disproteinization. Boiling also promotes the shortening of the average lenses life, so as to increment polymeric instability.


DISCLOSURE OF THE INVENTION

The present invention has the object of solving these problems providing a process for the preservation of hydrophilic lenses by freezing cold, a process that is simple, of low operational cost and developing no toxity at all.
Taking into consideration the problems found out with the precedent processes, the inventor of the present process discovered that on submitting hydrophilic lenses to freezing, the latter presented neatly cleaner, what has been demonstrated and proved in a practical and theoretical form.
Exhaustive studies and tests have demonstrated that hydrophilic lenses subjected to the process of this invention allow, not only to diminish the secretion, but to increment also in a sensible way, the usuary comfort, of lenses subjected to the freezing process. Another advantage, verified in the use of this process is that the risk of damage, compared to the preceding processes, is equal to zero, since the lenses support freezing for an indefinite time.
Another advantageous aspect of the process in the present invention is that the toxity is nill, since we only use a sodium

REFERENCES:
patent: 2854360 (1958-09-01), Pajes
patent: 3419427 (1968-12-01), Plock
patent: 3908680 (1975-09-01), Krezanoski
patent: 3948679 (1976-04-01), Lewis
patent: 4409034 (1983-10-01), Williams
patent: 4490389 (1984-12-01), Nelson et al.
patent: 4491484 (1985-01-01), Williams
patent: 4560491 (1985-12-01), Sherman
patent: 4585488 (1986-04-01), Giefer

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