Abstract
Purpose:
In previous work, altered morphology and poorer function of meibomian glands was found in contact lens wearers (CLWs) and previous CL wearers (PWs) than in non-wearers. The mechanism underlying these changes is unclear but as inflammation is known to accompany dry eye disease and contribute to its propagation, it may present as an aetiological component of eyelid tissue change.<br /> In this study, the aim was to investigate how levels of a marker of inflammation in the tears, matrix metalloproteinase-9 (MMP-9), changed, as a function of contact lens wear.
Methods:
Flush tears were collected from: (1) three groups of CLWs who had worn lenses on a daily basis for different durations (Short: 2±1 years, Moderate: 5±1 years and Long experience: 10±2 years); (2) a group of PWs who had ceased wear for at least 6 months; (3) healthy non-wearers as a control group. Total MMP-9 concentration was established using sandwich enzyme-linked immunosorbent assay. A one-way analysis of variance (ANOVA) with Bonferroni post-hoc correction was used for statistical comparison.
Results:
Flush tear samples of 100 participants (51 females; mean age ± SD: 25.4 ± 4.1) were analysed. CLWs with short experience had MMP-9 concentration (17.26 ± 15.58 ng/mL) that were significantly higher than NWs (2.84 ± 2.32 ng/mL; p <0.05). MMP-9 concentration for CLWs with moderate (11.08 ± 11.5 ng/mL) and long experience (11.36 ± 16.6 ng/mL) and PWs (9.62 ± 17.23 ng/mL) did not differ from NWs.
Conclusions:
MMP-9 increases during the early years of CL wear, paralleling the onset of morphological changes in the meibomian glands. This may be an indication of an inflammatory mechanism in meibomian gland dropout in CLWs.