Application Of A New Noninvasive Ocular Surface Interferometer For The Diagnosis Of Meibomian Gland Dysfunction

Purpose To compare the difference of lipid layer thickness(LLT)of the tear film measured by LipiView(?)ocular surface interferometer between patients with meibomian gland dysfunction(MGD)and normal population,and to evaluate the correlation between LLT and other diagnostic criteria for MGD,then we determine whether there is application value for the diagnosis in MGD.Methods A prospective case-controlled study was performed in department of ophthalmology,Qilu Hospital of Shandong University,from September 2017 to March 2018.93 MGD patients and 50 age-matched healthy controls were recruited.All subjects were underwent the six examinations sequentially as follows;evaluation of ocular surface disease symptoms using the Ocular Surface Disease Index(OSDI)questionnaire,lipid layer thickness of the tear film testing using the LipiView?ocular surface interferometer,tear film break-up time(BUT),fluorescein staining(FL),Schirmer I test,evaluation of the secretion function of meibomian gland(the scores of meibomian gland excretion ability and the character of the meibomian gland secretions).According to OSDI questionnaire,the patients of MGD were classified into mild symptom(12.0<OSDI≤22.0),moderate symptom(22.0<OSDI<32.0)and severe symptom(32.0<OSDI<100.0).In MGD group,the measurement data of LLT was converted into hierarchical data.LLI≥75 nm was defined as thick LLT group;60nm<LLT<75nm,moderate LLT group;LLT<60 nm,thin LLT group.By applying SPSS 19.0 for statistical analysis of the difference of each parameters between the MGD group and the healthy control group,the difference of each parameters among hierarchical LLT groups,and the correlation between LLT and the traditional diagnostic indicators of MGD in both MGD group and healthy control group.Results In this study,93 MGD patients(93 eyes)were observed.Among them,there were 42 male patients(42 eyes)and 51 female patients(51 eyes),whose age ranging from 18 to 72 years old,and the average age was(45.13±13.51)years old.In the healthy control group,50 healthy controls were recruited,which was made up of 23 male patients(23 eyes)and 27 female patients(27 eyes),who aged from 21 to 71 years old,averagely(41.74115.75)years old.There were no significant differences in age and gender between the two groups(P>0.05).LLT measured by LipiView(?)ocular surface interferometer was obviously thinner in MGD group(60.37±22.85)nm than that in healthy control group(70.80±18.97)nm,showing significant difference between the two groups(t=-2.758,P<0.05).Between them,respectively 55.9%,36.0%patients whose LLT<60nm,and 28.0%,42.0%patients whose LL≥75nm.The ratio of cases whose LLT<60nm in total MGD cases was significantly higher than in the control cases(P<0.05).The OSDI score was significantly higher,and BUT,Schirmer I was dramatically shorter in MGD group than the healthy control group,showing significant differences between the two groups(Z=-9.642,-4.777,-4.842,all at P<0.05).The mean score of meibomian gland excretion ability and meibomian gland secretion respectively were(3.70±1.86)and(3.52±2.15)in MGD patients compared with the mean value of(1.52±1.30)and(0.66±1.00)in the controls.MGD patients had significantly higher meibomian gland excretion ability score and meibomian gland secretion score compared with the healthy controls(t=7.358,10.811,all at P<0.05).In MGD group,10 patients’ corneal fluorescein staining was postive,and all healthy controls’ corneal fluorescein staining was negative.In hierarchical LLT groups,there were respectively 26 patients whose LLT>75nm,15 patients whose 60nm<LLT<75nm,52 patients whose LLT<60nm.The OSDI score of the three groups respectively was(24.27±12.69),(30.53±13.94)and(35.02±16.04),showing significant difference among the three groups(F=4.560,P<0.05).The proportion of patients with mild symptom,moderate symptom and severe symptom in the three groups was statistically significant(x2=17.039,P=0.001).The meibomian gland excretion ability score,meibomian gland secretion score,BUT and Schirmer I in the three groups were significantly different(F=44.259,14.768,16.091,3.642,all at P<0.05).For the MGD group,LLT showed significantly positive correlation with BUT(r=0.510,P<0.05),and was negatively correlated with OSDI score,meibomian gland excretion ability score,meibomian gland secretion score(r=-0.412,-0.720,-0.552,all at P<0.05).However,LLT had no correlation with corneal fluorescein staining score and Schirmer I(r=-0.101,-0.022,P=0.337,0.832).In the control group,there was no correlation between LLT and any other indexes(all at P>0.05).Conclusion LLT measured by LipiView(?)ocular surface interferometer was obviously thinner in MGD group than that in healthy control group.For MGD patients,LLT showed positive correlation with BUT.When LLT<60nm,BUT obviously became shorter.LLT showed important clinical significance for the indirect evaluation of tear film stability.Inversely LLT was negatively correlated with OSDI score,meibomian gland excretion ability score and meibomian gland secretion score.When LLT<60nm,the symptom was serious and the secretion function of meibomian gland was inferior.LLT was measured by LipiView(?)ocular surface interferometer by a noninvasive and automatic way,which showed an apparent correlation with other diagnostic criteria for MGD.This automated assessment of the LLT might be a suitable method for detecting and evaluating MGD.