Title:
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Longitudinal assessments of corneal and tear film characteristics after lasik versus continued contact lens wear
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Changes in oxygen availability, exerted mechanical force or even surgical manipulation are all
factors known to influence corneal characteristics, yet detailed information about the changes such
influence may induce is limited in ophthalmic literature. Furthermore, the appearance of the corneal
endothelium, which is often used as a presage of structural and functional changes taking place in
the cornea, has not been systematically studied over extended periods and information such as
endothelial morphometry is hence not available. The purpose of this study was therefore to
evaluate the endothelial morphometry over a two-year period in subjects who underwent different
types of intervention, either in the form of change in contact lens material, LASIK surgery or by
replacing existing contact lenses with a similar type. A group of spectacle wearers served as a
control group.
Results obtained through the course of the study revealed that subjects who continued wearing
conventional contact lenses had substantial amounts of polymegethism compared with the control
group. Those who had undergone LASIK surgery had significantly reduced amount of
polymegethism three months after surgery and reached a concentration level that was consistent
with the control group after 24 months. A similar tendency was found in the subjects who were
refitted with silicone-hydrogel (SiH) lenses although the high number of endothelial cells that was
found to reverse back to a six-sided shape after LASIK treatment was not apparent in this group of
subjects. This may be associated with the sustained inflammatory response, which is arguably
present in the corneas of these subjects.
LASIK surgery seems to have no detrimental effect on the corneal endothelium and the procedure
may even reverse some of the contact lens induced changes in the endothelial mosaic. Pre-ocular
tear film evaluation revealed no inferior quality or quantity nor did these subjects report any higher
dry eye sensation than the other subjects.
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