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A CLINICAL COMPARISON OF LIMBAL AND
EPITHELIAL ARCUATE LESIONS (SEALs) IN HIGH DK EW.
Nicole O'Hare, Thomas Naduvilath, Deborah F. Sweeney, Brien A.
Cornea and Contact Lens Research Unit, School of Optometry and
Cooperative Research Centre for Eye Research and Technology, University
of New South Wales, Australia.
SEALs have been observed to occur
in two locations during high Dk EW: - limbal (<0.8mm from the limbus)
- paralimbal (>0.8mm from the limbus).
The purpose of this study was to determine if the clinical
features, symptoms, exposure to high Dk EW and recurrence
rates associated with these 2 locations of SEALs were different.
Twenty four cases of SEALS
in 14 subjects wearing prototype high Dk lenses on a 6 or
30 night EW schedule were examined at the slit lamp biomicroscope
and completed a symptoms questionnaire at the time of presentation.
After white light examination (magnification, 16-25x) for
the presence of infiltrates, sodium fluoroscein was instilled
and the cornea was immediately examined with cobalt blue light
(magnification, 16x) and a thin optic white light section
(25-40x magnification) for depth of the staining. Chi squared
analysis was used to compare the proportion of the 2 locations
of SEALs and Fisher's Exact Test for the clinical features
of each group.
There was a significantly
higher proportion of limbal (71%) compared to paralimbal (29%)
events, (p=0.04). The incidence of diffuse infiltrates was
higher in the paralimbal (86%) compared to the limbal (41%)
group, (p=0.08). The paralimbal group also reported a higher
proportion of symptoms and had a higher recurrence rate in
the same eye, however this did not reach statistical significance.
While SEALs found within
0.8mm from the limbus are more prevalent, SEALs outside
this limbal zone maybe more likely to have underlying infiltration.