An In Vivo Confocal Microscopy Study Of Seasonal Allergic Conjunctivitis

Purpose:To observe the palpebral conjunctiva and meibomian gland condition in moderate seasonal allergic conjunctivitis(SAC)patients by in vivo confocal microscopy and analysis the manifestation.Design:Prospective,single-center,controlled study.Participants:All subjects were 16 to 40 years old young adults.Fourteen recurrent moderate SAC patients(28 eyes,7 males,7 females;mean age,25.9±5.9 years)were incorporated.12 normal subjects(24 eyes,6 males,6 females;mean age,30.6±7.6 years)had been recruited in normal control group.As a complement,14 obstructive meibomian gland dysfunction(MGD)patients(28 eyes,8 males,6 females;mean age,29.2 ± 8.2 years)were observed for clarifying the in vivo confocal microscopy characteristics.Methods:All subjects accepted history recording,symptoms rating,and clinical examinations including,slit-lamp microscope examinations,tear break-up time(BUT)measurements,fluorescein staining,infra-red meibography,pressing meibum test and IVCM scanning mainly on palpebral conjunctival epithelium,the conjunctival associate lymphoid tissue and meibomian gland structure.Statistical analysis was performed using Kruskal-Wallis test or simulate p value chi-squared test.Results:The symptoms questionnaire scores of SAC group(mean,10.4 ± 3.2)were significantly higher(p<0.01)than that of the normal control(NC)group(mean,1,3± 0.8).BUTs of SAC group(mean,8.0± 1.3 second)were lower than that of the NC group(mean,12.3 ± 2.2 second)(P<0.01).The pressing meibum scores and eyelid margin scores of SAC group(mean,1.1 ± 0.5&1.7 ± 1.1)were slightly higher than that of NC group(mean,0.5± 0.7&0.2 ± 0.4)(P<0.01).More inflaming cells infiltrated in the regional epithelial layer of palpebral conjunctiva in SAC patients(mean,989.1±203.8 cell/mm2)than that in normal controls(mean,89.5±14.9 U/mm2).Mean areas of section of meibomian gland acinar unit area and meibomian gland acinar unit of SAC patients(mean,1017.7±129.0 ?m2&118.6±15.1 U/mm2)were slightly lower than that of the NCs(1138.1±1 37.9 ?m2&124.4±19.0 U/mm2)(p<0.05).Conclusion:IVCM could be used to observe meibomian gland structure and inflammatory cell infiltration in the palpebral conjunctiva of moderate SAC patients.Meibomian gland acinar unit volume and density might slightly decrease during the onset of SAC,which need more research to verify.