cleaning and disinfection
2 main components of care system of contacts
Daily cleaner
used to remove debris from the lens surface from the surface of the contact lens - clean immediately after lens is removed - often used in Hydrogen Peroxide-based systems.
Benzalkonium chloride
a preservative primarily used as an antimicrobial agent and secondarily as a surfactant in GP lens disinfection system but not in soft lens disinfection system. It is responsible for killing microorganisms and inhibiting their future growth in RGP solutions.
Buffers
are used in solution to keep them in the range of ph 6 to 8. Includes agents such as citrates, phosphates, borates, and trimethamines.
disinfection
reduce the level of microbial contamination to a safe level
no rub solution
should still involve a digital rubbing of the lens surface
saline solution
use for rinsing only. Does not disinfect lenses - made to resemble tear with 0.9 sodium chloride -ph between 7.0 to 7.4
heat and chemical
ways to disinfect soft lens
sterilie
occurs when all viable microbes are eliminated
multi-purpose
clean and disinfect contact lens
Enzymatic cleaners
used to remove accumulations of tear proteins, predominantly lysozyme, from the contact lens surface
- Should be used on RGP lenses at least once per week to remove deposits.
- Enzymatic cleaning of soft lenses is important because it prevents the development of Giant Papillary Conjunctivitis, it prevent the lens from shrinking and tightening, and it maintains the hydration of the lens
artificial tear
acts as lubricating drops
Thimerisol
Mercury based preservative used in some cleaning solutions to aid in the prevention og bacteria growth in the solution. Less popular in recent years because some people have adverse reactions to it.
Hydrogen peroxide system
The most effective solution for removing deposits/all pathogens from soft contact lenses. They are more effective against viruses and fungi than most chemical disinfection systems. However, residual hydrogen peroxide from incorrectly disinfecting soft contact lenses can cause epithelial damage. In addition, the use of generic 3% hydrogen peroxide solutions can cause lens discoloration.
Polyquad
a preservative derived from the benzalkonium chloride. It was first used for the storage solutions of contact lenses. Today it is found in many eye drops such as artificial tears and antiglaucomatous. It is considered less toxic to the corneo-conjunctival surface
propylene glycol and hydroxypropyl methylcellulose (HPMC)
used in multi-purpose solutions as wetting / comfort agents
Combination wetting/soaking solutions
are used with RGP lenses to maintain lens surface wettability, to disinfect the lens, and to cushion the lens during insertion.