الفهرس 
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Abstract
The aim of this causal comparative cross-sectional observational study was to determine changes detected by non-contact meibography and non-invasive break up time test (NIBUT) in individuals with regular use of soft contact lenses and to compare these findings with irregular soft contact lenses wearers and non-wearers control group.
In our study, we used a modified Sirius® Scheimpflug Camera (C.S.O, Construzionne Strumenti Oftalmici, Florence, Italy; bon Optic VertriebsgmbH, Lübeck, Germany) with the Phoenix-Meibography Imaging software module to evaluate both non-contact meibography and non-invasive tear break up time.
In our study, three groups were recruited; group A(regular contact lenses wearers) including 36 eyes (21.7%), group B (irregular contact lenses wearers) including 50 eyes (30.1%) and group C as a control group (Non-wearers) including 80 eyes (48.2%). The studied age group was 18-35 years. Regular CL wear was defined as regular and prolonged wear of soft contact lenses (average more than 25 hours/ week during the last 6 months.
We found that OSDI was 15.17±8.12 and 15.61±8.25 in group A and B respectively, compared to 0nly 12.25±6.24 in the control group. There was statistically significant difference between CL wearers and non-wearers, while there was no difference related to the duration of CL wear.
In this study, we detected high statistically significant difference among the three groups related to percentage of MGL. In group A, MGL was 37.53% and 30.58% for UL and LL respectively. In group B, MGL was 23.12% and 21.44% respectively. In group C, MGL was only 15.33% and 12.33% respectively
In this study, high significant difference was detected among the three groups for the mean meibograde. It was 3.03±1.66, 2.86±1.78 and 1.99±1.07 for groups A, B and C respectively.
In our study, both NIF-BUT and NIAvg-BUT showed high significant difference among the three groups. The mean NIF-BUT was 8.42±2.77, 11.76±2.72 and 13.57±1.97 seconds respectively. Abnormal BUT (<10 seconds) was detected in 44.4% of group A, 24% in group B and only 17.5% in group C. The mean NIAvg-BUT was 8.12±2.42, 10.75±1.92 and 12.58±1.57 seconds respectively
In our study, there was positive correlation among the duration of contact lens wear, OSDI, total meiboscore and meibograde. On the other hand, the correlation was negative between these outcomes versus both NIF-BUT and NIAvg-BUT. Significant correlation was detected between the duration of CL wear and all other outcomes except OSDI. In addition, significant correlation was present between total meiboscore and both NIF-BUT and NIAvg-BUT. Also high significant positive correlation was reported between NIF-BUT versus NIAvg-BUT.
Conclusion:
Regular soft contact lenses wear is associated with significant Meibomian gland loss and less than normal tear break up time.