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Ocular surface bacteria affect tear film, may predict dry eye
Researchers from the Brien Holden Vision Institute are exploring whether an imbalance in ocular surface bacteria contributes to destabilization of the tear film and leads to irritation, inflammation and, ultimately, dry eye.
Judith Flanagan, PhD, ELS, and fellow researchers looked into factors that predispose a normal population to develop meibomian gland dysfunction (MGD).
The researchers explored 185 healthy subjects divided into four age groups: 25 to 34 years old, 35 to 44 years old, 45 to 54 years old and 55 to 66 years old; the ratio of females to males was 109:76.
At a single visit, eyelid margins were swabbed and bacteria cultivated.
They looked for associations between the bacterial burden of the lower eyelid margin and meibomian gland, tear film parameters and dry eye symptoms.
The study results were analyzed in the last 12 months and have not yet been published, according to Flanagan, in an interview with Primary Care Optometry News.
Meibomian gland evaluation included meibum quality, the ability of the gland to be expressed and gland dropout assessment. Clinical examination also included tear meniscus height, osmolarity, noninvasive and invasive tear break-up-time, and other anterior eye variables, she said.
“Significant associations with increased bacterial burden included males vs. females; middle-aged group of females (45 to 54 years old) vs. younger and older women; worsening meibum quality overall; and worsening meibum quality in females; females for whom we could not express any meibum vs. those we could express meibum from; and males and females who had a reduced tear meniscus height and worse tear break-up time, increased tear osmolarity, and increased palpebral roughness and redness,” Flanagan said.
“Increased bacterial burden is associated with deterioration in clinical measures such as meibum quality and expressibility in females and decreased tear film stability in an otherwise healthy population with no overt signs of MGD,” she added.
Even in a normal population, there appear to be changes associated with an increased presence of bacteria that affect the tear film and may predict those who will to develop overt dry eye disease in the absence of preventive measures, she concluded. – by Abigail Sutton
Disclosures: Flanagan reports no relevant financial disclosures.