Predicting extended wear complications from overnight corneal swelling.
OBJECTIVE
To examine the hypothesis that the corneal overnight swelling response (ONSR) is a predictor of ocular complications in contact lens extended wear (EW).


METHODS
The Berkeley Contact Lens Extended Wear Study (CLEWS) was a randomized, concurrently controlled clinical trial in which more than 200 subjects in EW with rigid gas-permeable (RGP) lenses were observed for 1 year. After adapting to EW, subjects were randomized to either medium or high oxygen-permeable (Dk) RGP lenses and underwent clinical assessments, keratometry, and corneal pachometry at 3-month intervals.


RESULTS
The ONSR was directly related to lens Dk (P = 0.01) and exhibited substantial variability across subjects. The probability of remaining free of complications over time was not significantly lower for subjects with a mild ONSR compared with those with greater edema (P = 0.84). The risk of development of keratopathy was not significantly related to the ONSR (relative risk = 1.00).


CONCLUSIONS
The corneal ONSR is not a good predictor of ocular complications in 1 year of RGP EW. Lenses that cause little or no corneal edema are not necessarily safer for overnight wear.
Graham
A D
AD
School of Optometry, University of California, Berkeley, CA 94720-2020. agraham@spectacle.berkeley.edu
Fusaro
R E
RE
Polse
K A
KA
Lin
M C
MC
Giasson
C J
CJ
D002940:Circadian Rhythm; D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects*; D003316:Corneal Diseases / Q000209:etiology; D015715:Corneal Edema / Q000209:etiology*; D004867:Equipment Design; D005544:Forecasting; D006801:Humans; D010100:Oxygen; D010539:Permeability; D011446:Prospective Studies; D018570:Risk Assessment; D013997:Time Factors
D010100:Oxygen