The Influence Of Overnight Orthokeratology (Ortho-k) On Tear Film In Adolescent Myopia Patients

Objective: To observe the changes of tear film stability before and after wearing overnight orthokeratology in adolescent myopia patients and analyze its trend.To evaluate the application value of Keratograph 5M in the evaluation of tear film in adolescent patients.Methods: Prospective study.From March 2017 to September 2017,50 cases(96 eyes)of adolescent myopia were selected from the fourth affiliated Hospital of China Medical University.The invasive tear break-up time(IBUT)with fluorescein sodium staining and non-invasive ocular surface analysis instrument(Keratograph 5M,Oculus)were used to check up.The patients with juvenile myopia were followed up before and after wearing.The main indicators were tear break-up time(IBUT)with fluorescein sodium staining,tear meniscus height(TMH),non-invasive first break-up time(NIBUT(f)),non-invasive average break-up time(NIBUT(av)).The data were analyzed statistically.Result: 1.Tear break-up time: the time of tear film rupture was significantly shorter at 1 week after wearing the lens than that before(P<0.05).The IBUT,NITBUT(f),NIBUT(av)of 1mo was still lower than that before(P=0.045,P=0.010,P=0.002),but it was higher than that of 1w(P=0.043,P<0.001,P=0.002).After 1m,the indicators,measured in each period of time after the wear was no significant difference between before and after wear(P>0.05).2.Tear meniscus height: There was no significant difference in the height of lacrimal river between before and after wearing corneal plastic lens(P > 0.05).3.The Spearman-related analysis showed a significant positive correlation between NIBUT(f)and NIBUT(av)(r=0.69,P<0.001).There is a positive correlation between IBUT and NIBUT(f),IBUT and NIBUT(av)(r=0.128,P=0.005;r=0.155,P=0.001).Conclusion: The stability of tear film decreased in the early stage after the juvenile myopia patients first wear the overnight corneal contact lens,but then recovered to the pre-wear level and tended to be stable.As a non-invasive inspection device,Keratograph 5M ocular surface analyzer can evaluate lacrimal film function quickly and objectively,and provide reference for clinic.