As the tear film ages it becomes less stable and more susceptible to damage associated with dry eye disease—but the process by which these changes occur has not been clear.1 Now, new research shows that distinct differences in the composition of the tear film itself exist between age groups.
The research team—based out of Aston University in Birmingham, UK—looked at two age groups, a “younger” group where the mean age was approximately 23 years old, and an “older” group where the mean age was approximately 63 years old.2 They looked at objective, structural clinical measurements in each group, including tear volume, tear film stability and tear protein analysis, as well as overall ocular health. The study also used subjective patient reports, such as the McMonnies index questionnaire, which evaluates for dry eye. The older group experienced elevated McMonnies scores, higher plasma-derived albumin levels and more instances of bulbar redness than the younger group. The younger group had larger tear meniscus heights.2 The tear protein analysis was significantly different too, showing a protein peak at approximately 23kDa in 53% of the older group, but in only 36% of the younger subjects.2
Specific correlations between clinical measurements and biomarkers for individual subjects were not observed, the researchers report.
1. Mathers W, Lane J, Zimmerman M. Tear film changes associated with normal aging. Cornea. 1996;15(3)229-34.
2. Mann A, Campbell D, Mirza Z, et al. Clinical and biochemical analysis of the ageing tear film. Bri J Ophthalmol. May 11, 2019. [Epub ahead of print].