Background Tear film stability is important for healthy visual function, and yet little is known of the ageing mechanisms. The aim of this study was to investigate parallels between biochemical changes and clinical physical parameters, which occur in the tear film of two subject populations differing in age by over 30 years.
Methods Two distinct age groups were chosen: 11 ‘younger’ (23.7±2.1 years) and 19 ‘older’ (63.0±4.0 years) subjects. A series of clinical tests were performed to access tear volume, tear film stability and general ocular health. Tear protein analyses from extracted Schirmer strips were conducted with the Agilent 2100 Bioanalyzer.
Results Clinical investigations highlighted significant differences between the age groups. For example: McMonnies scores (p=0.009) and bulbar redness (p=0.038) were higher for the older group, whereas tear meniscus height was larger (p=0.018) in the younger group. Similarly, relative plasma-derived albumin levels were higher (17.1%±12.4%) in the tears of the older, compared with the younger (5.0%±9.6%) group. A protein peak at ∼23 kDa was observed in 53% of the older group samples but in only 36% of the samples of the younger subjects (p=0.122).
Conclusions Distinct differences in tear film composition between the two age groups were observed. Parallels in terms of clinical symptoms which reflected a biochemical response (and vice versa) were found, but specific correlations between clinical measurements and biomarkers for individual subjects were not observed.
- tear protein
- tear film stability
- corneal haemostasis
- ageing biomarkers
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Contributors Study conception, design, progress, interpretation and data analysis of the results were executed by AM and DC. Clinical measurements were performed by ZM and DC under the supervision and direction of OH and JSW. The laboratory biochemical analysis, tear collection, final assessments, decisions and article preparation were undertaken by AM. The manuscript was written by AM and DC and BJT, and JSW corrected the final manuscript. The laboratory biochemical analysis, tear collection, final assessments, decisions and article preparation were undertaken by AM.
Funding British Contact Lens Association Summer Research Scholarship (£1,500 for eight weeks for one student).
Disclaimer The views expressed in the submitted article are those of the titled authors and not an official position of the institution or funder.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval All the studies described herein had received prior ethics approval by the appropriate committee at Aston University.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement The data sets generated and analysed for this study are available from the corresponding author upon reasonable request.