Objective:To explore the relationship between contact lens (CL) related dry eye and morphological changes of meibomian glands.Methods:A cross-sectional study was performed.A total of 157 consecutive subjects (314 eyes) to underwent refractive surgery from May 2014 to June 2015 in Tianjin Medical University Eye Hospital were included.The subjects wearing soft CL for a long time were divided into CL group (182 eyes of 91 subjects), while the subjects who never wore CL were divided into the control group (132 eyes of 66 subjects). The ocular surface disease index (OSDI) questionnaire, tear meniscus height (TMH), first non-invasive tear film breakup time (fNIBUT), average non-invasive tear film breakup time (avNIBUT) and corneal fluorescein staining (CFS) score of all subjects were collected and analyzed.Morphological evaluation of meibomian glands were performed.The meibomian glands dropout ratio of upper eyelid, lower eyelid and total meibomian gland area as well as meibomian glands distortion number of the two groups were compared.This study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Tianjin Medical University Eye Hospital (No.2014KY[L]-09). Written informed consent was obtained from each patients prior to any examination.Results:The OSDI score, CFS score, TMH, fNIBUT and avNIBUT were 16.67(10.00, 25.00), 13.88(7.50, 18.26), 0.20(0.17, 0.23) mm, 5.64(3.95, 7.92)s and 8.56(6.56, 12.12)s in CL group, respectively, while 13.88(7.50, 18.26), 1.00(0.00, 2.00), 0.22(0.17, 0.29) mm, 7.33(4.54, 13.21)s and 11.49(7.46, 17.83)s in the control group, respectively.Compared with the control group, the CL group had the higher OSDI score, higher CFS score, lower TMH, lower fNIBUT, lower avNIBUT, and the differences were significant (all at P<0.01). The MG dropout ratio and meibomian gland distortion number were (29.42±12.24)% and 4(3, 6) in CL group, respectively, while (20.37±10.83)% and 3(1, 4) in the control group, respectively.In comparison with the control group, the CL group had the higher MG dropout ratio and greater meibomian gland distortion number ( t=6.76, P<0.01; U=7 656.00, P<0.01). A positive correlation was found between the total meibomian gland area dropout ratio and duration of CL wearing ( rS=0.404, P<0.01), OSDI scores ( rS=0.275, P<0.01), CFS scores ( rS=0.319, P<0.01). Conclusions:Long-term wearing of CL can lead to severe ocular discomfort, dry eye syndrome and morphological alterations in meibomian gland, suggesting that morphological abnormality of meibomian gland is presumably associated with the occurrence of ocular discomfort and dry eye syndromes in CL wearers.

Objective:To evaluate the effect of peripheral defocus soft contact lenses (PDSCLs), single-vision spectacles and single-vision contact lenses (SVCLs) on the progression of myopia in children and adolescents.Methods:A meta-analysis was conducted.To collect relevant studies on the myopia control effect of PDSCLs in children, English databases including PubMed, Medline, Embase and Cochrane library were searched with myopia, contact lens, children, adolescents, myopia progression, axial length, refractive error and relevant free English terms as key words.Chinese databases including CNKI, Wanfang and VIP were searched with corresponding Chinese phrases and relevant free Chinese terms as key words.Randomized controlled trials (RCTs) on the myopia control effect in children and adolescents, with PDSCLs wearer as experimental group and single-vision spectacles or SVCLs wearer as control group, were independently collected by two researchers.Quality of included studies was evaluated with the Cochrane tool to assess risk of bias for RCTs.Combined effects of change in refraction and axial length between experimental and control groups was calculated by weighted mean difference (WMD) and 95%confidence interval ( CI). The heterogeneity of included studies was evaluated by I2 statistic.The refraction and axial length of experimental and control groups were compared by Z test.Myopia control effect of different PDSCLs add powers was analyzed by subgroup analysis.The experimental data with add power ≤+ 2.00 D, low aberration and low depth of focus were assigned to low-medium add power subgroup, and the experimental data with add power >+ 2.00 D, high aberration and high depth of focus were assigned to high add power subgroup. Results:A total of 378 publications were retrieved.Finally, 10 high-quality RCTs and 14 groups of data were included in this meta-analysis.In these studies, 1 645 myopic children aged from 6 to 18 years were enrolled, including 808 cases in experimental group and 837 in control group.The follow-up ranged from 10 to 36 months.Among the 10 studies, there were two crossover trials without a washout period, so only the first intervention results were included.According to the meta-analysis, the change in refraction in experimental group was significantly less than that in control group (WMD=0.22 D, 95% CI: 0.15-0.30, Z=5.65; P<0.05). The change in axial elongation was significantly less in experimental group than control group (WMD=-0.10 mm, 95% CI: -0.12--0.09, Z=12.28; P<0.05). Subgroup analysis showed that the WMD of refraction change and axial elongation between experimental and control groups were 0.21 D (95% CI: 0.10-0.31) and-0.10 mm (95% CI: -0.13-0.08) in the low-medium add power subgroup, respectively, and were 0.26 D (95% CI: 0.13-0.38) and -0.13 mm (95% CI: -0.15--0.10) in the high add power subgroup, respectively. Conclusions:PDSCLs have better myopia control effect than single-vision spectacles and SVCLs in children and adolescents.When the add power is higher, PDSCLs can slow the progression of myopia more effectively.