Abstract
Purpose :
To measure the activity of inflammatory cytokines and proteases in the tear film reservoir and in the ocular surface tears during acute scleral gas permeable lens (SGP) wear.
Methods :
Normal, habitual soft contact lens wearers (SGP neophytes) were fit with SGPs, and each wore the lenses daily for three days. At experimental visits, tear samples were collected from the ocular surface tears (OST: outside of the SGP margin) and from the tear film reservoir (TFR: the fluid between the SGP and the ocular surface), and tear mediator concentrations were compared between pre-SGP (baseline) samples and post-8h wear samples, as well as between baseline and post-3d wear samples. The tear samples were tested for inflammatory cytokines (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17A, IFN-γ, TNF-α) and proteases (matrix metalloproteinases (MMP)-1, -7, -9, -10, and tissue inhibitors of metalloproteinases (TIMPs 1-4)).
Results :
The mean volume of TFR collected from subjects in this study was 40 ± 46 µl (range 0 – 250 µl) and the mean OST volume collected was 14 ± 8 µl (range 2 – 25 µl). Median IL-4 concentration in the OST increased from baseline (median 15.4 pg/µl, IQR 18.4) after 8 hours of wear (median 31.7 pg/µl, IQR 11.4), although the difference did not reach significance (p=0.17). After 3 days of wear, IL-4 had returned to the baseline range (9.76 pg/µl, IQR 8.15) showing no significant difference from the baseline concentrations (p=0.98). MMP-9 concentrations increased in the tears after 8 hours of wear (baseline median: 0 pg/µl, IQR 910; post 8h median: 716 pg/µl, IQR 535), and showed a trend in lowering in concentration after 3 days of lens wear (468.6 pg/µl, IQR 674.8), although no significant difference was found. TIMPs were present in all tear samples, and there were no significant differences between the concentrations. There were no detectable concentrations of TNF-α, IL-17a, IL-12, IFN-γ, IL-1β, or IL-2 in the tear samples before or after SGP wear.
Conclusions :
Acute SGP wear modulates the production of certain cytokines and proteases in normal patients, although several inflammatory mediators that are present during infection and active inflammation are not observed in the tear film during SGP wear, indicating that these lenses may not excite a strong inflammatory response in the tears of a normal individual.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.