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Contact lens usage is associated with problems such as coating
and deposits on the lenses. During normal wear, dirt, protein
particles, lipids, bacteria, filamentous deposits, environmental
contamination like oils, smoke, lotions, make up and substances
transferred from hands can get on soft contact lenses. All these
together, as well as violation of contact lens care protocol,
can lead to ocular complications. Problems can include ocular
inflammation and allergic reactions like giant papillary conjunctivitis
and infection as well as problems of diminished visual quality,
irregular surface, poor wetting of lenses, poor fit and decreased
oxygen transmission to the cornea.
Proper cleaning and disinfection of contact lenses can remove
all lens coatings and deposits. A surfactant cleaner should be
used on a daily basis and an enzyme used weekly or bi weekly.
Despite approval of no rub cleaning solutions by the U.S. FDA
many practitioners believe that manual rubbing of the contact
lenses in the palm of the hand is necessary for complete cleansing.
There are usually two ways in which disinfection can be carried
out. Thermal disinfection and chemical disinfection are two methods
to kill germs causing serious eye infections and other complications
like less than optimal performance of lenses. They also protect
the eyes from irritation and the cleaning process helps remove
substances which shorten the life of the lenses. In thermal disinfection,
heat is used to kill the germs while in chemical disinfection
only disinfecting chemicals are used in cleaning.
Chemical Disinfection
This process of disinfection is more popularly used than thermal
disinfection. However, the doctor will decide whether your lenses
will require thermal or chemical disinfection. When the doctor
recommends chemical disinfection, the procedure is typically as
follows. Cleaning, rinsing, disinfecting and rinsing again. It
is imperative that soft contacts be disinfected every time they
are taken out and before reinsertion. Both daily and extended
wear lenses must be cleaned every night and though the extended
wear contacts are in theory not needed to be taken out every night,
most doctors recommend that to avoid complications they should
be disinfected nightly. With disposable contact lenses, cleaning
and disinfecting is not applicable, as they should be used once
and then they are taken out and thrown away after the specified
time period.
The procedure for cleaning requires different solutions for cleaning,
disinfecting and rinsing. A proper case in which to place the
lenses for cleaning after removal is required. The case should
be free of germs and deposits.
Firstly, hands should be thoroughly washed with soap and water
before handling the lenses. While removing the lenses, the handling
should be gentle as rough handling may cause lenses to tear. Also
corresponding lenses for left and right eye should be noted. It
is recommended that the lens for the right eye is removed first.
After removal, the lens should be put in the palm of the hand
in a position that it curves like a bowl. Now a few drops of the
cleaning solution, which is to be used daily should be poured
on the upturned lens. Only with one finger the lens should be
rubbed back and forth. This will help to dissolve the dirt and
oils. After cleaning, the lens can be cradled on the fingertips
and rinsed well with a sterile saline rinsing solution. After
rinsing, the contact lens case is to be filled with a prescribed
disinfecting solution and the corresponding lens is to be put
in the corresponding side of the case.
The same steps mentioned must be followed in case of the other
lens. It is ideal if the lenses are soaked overnight but if that
is not possible then they must be soaked at least for the minimum
time as per instructions. Before reinserting the lenses, hands
should be washed thoroughly and the lens should be washed again
with the sterile solution and then put on. The case should be
rinsed with plain water and dried.
Thermal Disinfection
The procedure for thermal disinfection includes cleaning, rinsing,
disinfecting with heat and re-rinsing. In this case, a thermal
disinfecting unit is required as well as a special contact lens
case and a recommended solution which can be used with the heating
unit are required. The steps are the same as in chemical disinfection,
except that in the last step of disinfection the caps should be
screwed on the case and the whole thing is to be put on the heating
unit. The unit should be plugged on and switched. Before using
the heating unit the instructions should be read. A heating unit
usually takes 40 minutes to disinfect the lenses and then cools
down. After the whole process, the lenses can be inserted once
more. Before this, however, you can rinse the lenses with the
sterile saline solution.
Enzyme Cleaning
This is to remove protein deposits and is usually done every
week or bi weekly. Noting down the day in which cleaning is to
be done will aid in better maintenance. However, certain enzymes
are made to be used with thermal disinfection while others are
for chemical disinfection, so using the appropriate one is vital.
The enzymes are in the form of tablets.
Solutions for Cleaning
There are various solutions available but only certain ones are
applicable to certain users as different solutions may irritate
and discolor the lenses, so it is always better to use the doctors’ recommended
solution.
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