The Short-term Influence Of Overnight Orthokeratology On Tear Film In Young Myopia Patients

Objective:To investigate the changes in tear film of short-term overnight orthokeratology treatment in young myopia patients.Method:Thirty adolescents(60 eyes) with low and moderate myopia(-3.57±1.22) D, aged 10.8±2.7, divided into low myopia group and moderate myopia group according to the degree of myopia, divided by age 7~12 years old and aged 12~17, according to the sex and divided into two groups; according to the corneal flat corneal curvature for low curvature(<43D) group and high curvature group(≥43D), were included in the study and fitted with overnight orthokeratology contact lens. Subjective refraction, corneal topography, tear break up time(TBUT), Schirmer I test, and corneal fluorescent( FL) were checked. All of the measurements were taken at pre-wear, 1 day, 1 week, 1 month and 3months after orthokeratology.Results:All measurements changed significantly during the treatment except for Schirmer I test: the degree of myopia(spherical equivalent refraction) and corneal curvature was reduced at each follow-up time point(P<0.05); After the first month, the degree of myopia(spherical equivalent refraction) and corneal curvature changes decreased slightly and stabilized(P>0.05);TBUT also decreased at each follow-up time point(P<0.05), after the first week, TBUT changes decreased slightly and stabilized(P>0.05); There was significant difference between Low myopia group and moderate myopia group, different age group in TUBT during the 3 months of orthokeratology treatment(P<0.05); There wasno significant difference between different gender groups at pre-wear(P>0.05) and significant difference at each follow-up time point after orthokeratology(P<0.05). There was no significant difference between the different corneal curvature groups at all time points(P>0.05). There were no significant differences in tear volume during the 3 months of orthokeratology treatment(P>0.05);Eyes with corneal fluorescent increased and were mainly grade I during the treatment(6.7 %, 18.3 %, 23.3 %, 26.7 % and 25.0 % at pre-wear, 1 day, 1 week, 1 month and 3 months,respectively); In each follow-up time point, there was a positive correlation between the changes of TBUT and corneal curvature(P<0.05).Conclusion:Overnight wear of orthokeratology made tear film stability decreased obviously and the decline of the tear film stability mainly occurred in the first week after orthokeratology,and corneal shape changes are closely related. Drop of tear film stability aside from changes associated with the shape of the cornea, and the degree of myopia, age, sex also certain correlation, and had no significant correlation with the corneal curvature value.