Meibomian Gland Conditions In Visual Display Terminal Workers

The sebaceous meibomian glands(MG) in the eyelids, that synthesis, storage and secrete lipids for the superficial tear film layer, play an important role in maintaining a healthy ocular surface. Meibomian gland dysfunction (MGD) is one of the most commonly ocular surface disease in clinical practice, but the symptoms of MGD have no specificity, the consideration and examinations of meibomian gland abnormalities were easy to neglected by ophthalmologists. In the year of2011, the international workshop had published the definition of MGD; a chronic, diffuse abnormality occurs in meibomian glands, the features are terminal duct obstruction and/or qualitative/quantitative changes in the meibomian gland secretion (meibum). MGD may affect the tear function; evoke ocular discomfort symptoms and ocular surface inflammation and other diseases. Abnormalities in meibomian gland morphology can lead to meibomian gland dysfunction, which can be the cause of evaporative dry eye. The observation techniques and appliances of meibomian gland morphology in clinic are meibography and in vivo laser scanning confocal microscopy (LSCM) at present.With the advances of science and technology, visual display terminals (VDT) has been increasingly used, such as computers, tablet computers, video operation screen, as well as mobile phones, and other digital electronic devices. Working related to visual display terminals is also increasing dramatically in this global information age. The overwhelming prevalence of VDT evoke human concerned about the accompanied health problems, long time VDT using has been shown to be associated with ocular discomfort and vision problems, musculoskeletal disorders, and mental health, these syndromes were named as "visual display terminal syndrome". The ocular and vision discomfort are the most common complaints among VDT users. Dry eye was considered a significant contributor to the ocular symptoms in VDT users. The development of ocular complaints among VDT workers was also reported to be correlated with the meibomian gland dysfunction. The present study evaluated the morphologic characteristics and function of meibomian glands using this non-contact imaging device in a relatively large population of VDT workers. This clinical investigation for the first time revealed an important phenomenon that meibomian gland dysfunction not only associates but also determines the severity of the dry eye conditions in long term workers at visual display terminal.Propose:To explore an interesting phenomenon and mechanism that meibomian gland dysfunction (MGD) may determine the severity of the ocular discomfort and dry eye conditions in visual display terminal (VDT) workers with normal tear volumes.Methods:One hundred and six eyes of53consecutive patients working at a VDT for more than4hours a day were recruited for this study (Long time VDT group). Eighty eyes of40age-and gender-matched patients working at a VDT for less than4hours a day were served as controls (Short time VDT group). After completion of an Ocular Surface Disease Index (OSDI) questionnaire, the following tests were performed:tear film breakup time (BUT), corneal fluorescein staining score, tear production by Schirmer test without topical anesthetic, a slit-lamp examination of the lid margin abnormality and meibum expression, and an evaluation of the meibomian glands by Keratograph5M.Results:The dry eye indexes, OSDI and fluorescein staining score were significantly higher while the tear film BUT was dramatically shorter in the long VDT group than that in the short VDT group. However, the average of tear volumes measured by Schirmer test were in the normal ranges in both groups,11.53±8.32and12.88±9.66mm, respectively. Interestingly, the lid margin abnormality score, meibum score, and meiboscore were significantly higher in the long VDT group than the short VDT group (P<0.0001). When the low and normal tear groups were separated from the long VDT workers,52eyes with Schirmer<10mm, and54eyes with Schirmer>10mm, no significant difference was found between the two subgroups in OSDI, fluorescein staining and BUT, as well as the lid margin abnormality score, meiboscore, and meibum score. Spearman analysis further revealed that all3MGD scores were positively correlated with VDT working time (P<0.0001) and fluorescein scores (P<0.0001), inversely correlated with BUT (P<0.05), but not correlated with Schirmer values, in VDT workers.Conclusions:In conclusion, this study revealed that long time VDT workers who suffered ocular discomfort and dry eye syndrome without significant aqueous tear volume deficiency, but with significant alterations in meibomian gland morphology and function, suggesting that meibomian gland function is responsible for the severity of dry eye conditions in these patients. Moreover, longer durations of VDT work may cause MGD earlier, faster, or more severe than tear volume deficiency. Therefore, the examination of meibomian gland morphology and function, especially meibography, may provide early diagnostic and therapeutic values in dry eye disease.