Soft lens extended wear affects epithelial barrier function

Abstract

ObjectiveTo explore the impact of eye closure and soft contact lens extended wear (SCLEW) on epithelial permeability to fluorescein (Pdc). DesignA prospective cohort study. ParticipantsThirty-one noncontact lens (CL) wearers participated. InterventionThe effects of eye closure on Pdc were evaluated by comparing morning (am) and afternoon (pm) measurements on non-CL subjects. The effects of SCLEW on Pdc were determined by measuring Pdc before beginning SCLEW and then after 2, 4, and 12 weeks of SCLEW. Main outcome measuresPdc measured in the morning versus the afternoon and before versus after SCLEW was examined. ResultsAnalyses of Pdc were done using the natural logarithm (In). The mean ± standard error (SE) In(Pdc) measured in the am versus pm on 16 non-CL wearers did not differ significantly (−2.56 ± 0.16 vs. −2.69 ± 0.15, respectively; P = 0.46). In contrast, the mean ± SE ln(Pdc) in 15 subjects after 2 (−1.73 ± 0.183, P < 0.001), 4 (−1.59 ± 0.188, P < 0.001), and 12 weeks (−1.99 ± 0.206, P = 0.02) of SCLEW was substantially greater than that measured before lens wear (−2.42 ± 0.159 ln(nm/sec)). Interestingly, the mean ± SE In(Pdc) measured in the afternoon on seven subjects after 13 weeks of SCLEW was similar to their average baseline In(Pdc) (−2.62 ± 0.27 vs. −2.52 ± 0.243, respectively; P = 0.54). Further analysis showed that Pdc was highest in the morning and decreased approximately 12.5%/hour (P < 0.001) during the day. ConclusionsSleeping without CLs does not appear to alter Pdc; however, 2 weeks of SCLEW caused a 99% increase in permeability without observable changes by slit-lamp examination. Increases in Pdc appear greatest in the morning after SCLEW and then decrease exponentially during the day. Whether changes in Pdc will predict CL-associated keratopathy needs further study.