ABSTRACT
Objective To observe the changes in tear quantity and tear break-up time(BUT) before and after wearing overnight orthokeratology (OK),and investigate the influence of OK on tear film in young adolescents.Methods Prospective clinic study was conducted in 60 adolescents,aged 8-16 years,who met the inclusion criteria during November 2016 and May 2017 in the Second Hospital of Dalian Medical University were chosen and fitted with OK (OK group).At the same time,60 adolescents who met the same requirement were fitted with spectacle (spectacle group).The two groups were both divided into three subgroups according to the age (subgroup of 8-10 years old,11-13 years old,and 14-16 years old).The BUT,Schirmer' s I test score,and corneal fluorescent (FL) were measured and recorded before wearing and 1 week,1 month,3 months,6 months and 12 months after wearing.Results Totally 57 patients in the OK group (114 eyes) and 59 patients in the spectacle group (118 eyes) completed the follow-up study.No significant difference in Schirmer' s Ⅰ test scores was observed between the OK group and spectacle group (all P＞0.05).The BUT in OK group was significantly lower than that in the spectacle group at all the time points (all P ＜ 0.05).Of all subgroups,the subgroup aged from 8-10 years exhibited the sharpest and most rapid reduction in BUT.Conclusion Based on our findings,long-term OK wearing has no effect on tear volume but reduces the stability of tear film.The results suggest that OK should be considered to be a good alternative for children and adolescents with spectacle;however,it may influence the quality of tear film.In addition,special attention should be paid to younger adolescents,and regular follow-up is needed.