CONTACT LENS-OCULAR SURFACE INTERACTIONS
IN SUPERIOR EPITHELIAL ARCUATE LESIONS (SEALS)
Nicole O’Hare, Fiona Stapleton, Thomas Naduvilath, Isabelle
Jalbert, Deborah F. Sweeney, Brien A. Holden Cooperative Research
Center for Eye Research and Technology, University of New South
Wales, Sydney, Australia. |
|
| Purpose:
|
| Cases and controls were compared to
determine contact lens (CL)-ocular surface interactions
associated with SEALS in high Dk extended wear (EW). |
| Method: |
| Seventeen cases of SEALS
were matched to 17 controls for age, sex, duration of high
Dk EW, refraction, and wear schedule. High Dk CL wear experience
ranged from 3 to 24 months at the time of analysis. Fitting
and surface characteristics of the CLs, measured at regular
intervals, were compared between cases and controls during
the period of EW. These selected variables were also compared
for the SEALS cases at the time of the event to their respective
prior-to-event phase. At a single visit, CL cytology using
the habitual CL was performed. Corneal epithelial cells were
harvested from the back surface of the CL, stained, and counts
determined. |
| Results: |
| Wettability was slightly
but not statistically significantly lower, (1.8 ± 0.6
versus 2.0 ± 0.4, p=0.09) and horizontal centration
was better (0.0 ± 0.1mm versus 0.1 ± 0.1mm,
p=0.01) for the SEAL cases than the controls over the period
of EW. At the time of the event, tightness was higher (49
± 6% versus 45 ± 9%, p=0.06) and primary gaze
movement was lower (0.2 ± 0.1mm versus 0.3 ±
0.2mm, p=0.04) than the respective prior-to-event phase for
the SEAL cases. Higher numbers of corneal epithelial cells
were recovered from SEALS cases compared to controls (p<0.01).
|
| Conclusions: |
| Subjects with poorer
wettability and tighter fitting CLs seem to be more likely
to develop SEALS in these types of materials. Interaction
between the corneal epithelium and the lens back surface,
evidenced by corneal epithelial cell recovery, appeared
to be more pronounced in the SEALS cases. As SEALS appears
to be full thickness, ‘mechanical’ lesions, these
results suggest the hypothesis that ‘shear’ forces
leading to excessive disruptive interaction with the ocular
surface are exacerbated by poor wettability and tight fittings. |
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