Purpose:
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The interaction of lipoidal species
with surface and matrix of soft contact lens materials is
important in the development of spoliation resistant contact
lenses and successful ocular prostheses. Lipids are highly
reactive molecules, which interact with the surface of a
contact lens and are also readily absorbed into the lens
matrix. Once in the lens matrix these species are no longer
in close contact with the antioxidants in the superficial
tear layer and may alter their chemical structure. These
altered lipoidal species are less readily desorbed from
the lens matrix and may provide a site for further deposition
to occur. The aim of this study was to profile the type
of extractable lipids from dairy disposable and thirty night
continuous wear contact lenses. |
Method: |
A number of contact lenses,
which had been worn on a daily wear basis or for thirty nights
continuously, were collected. The gross levels of lipids were
assessed using fluorescence spectrophotofluorimetry on collection
and after extraction of the lipids for further analysis. The
lipid profiles were determined using high performance liquid
chromatography. |
Results: |
The lipid patterns for
both the surface deposition and extractable lipid profiles
were variable between patients. Patient-based effects outweighed
those related to wear time. The type of lens material also
played a role in the type of lipid laid down on the lens. |
Conclusions: |
Variations in patient
lipid deposition profiles are known to be greater than protein
deposition patterns. Although wear period is a progressive
driver of deposition it is outweighed by materials dependence
and patient to patient variation. Wear time becomes an important
issue for the small but significant number of heavy lipid
spoilers. There is a need to match the patient to the lens
type and wear schedule in order to minimize these problems. |
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