Clinical and biochemical analysis of the ageing tear film

Abstract

BackgroundTear 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.MethodsTwo 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.ResultsClinical 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).ConclusionsDistinct 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.

Vision through Healthy Aging Eyes

“…A study was specifically designed to investigate the changes in tear stability and compared both biochemical and physical parameters in two cohorts separated in age by over 30 years, the older group 63.0 ± 4.0 years. A few correlations between the clinical and biochemical responses were found such as corneal staining and bulbar conjunctival redness, which coincided with elevated albumin (a biomarker for vascular permeability) and a decrease in lysozyme, lipocalin and lactoferrin proteins (the primary aqueous secretory tear proteins), which is often clinically expressed as a reduction in the tear flow rate and tear break-up time [41].…”

Longitudinal Tear Protein Changes Correlate with Ocular Chronic GVHD Development in Allogeneic Hematopoietic Stem Cell Transplant Patients

“…A recent meta-analysis suggested LACTO level in tears is a good candidate as dry eye syndrome diagnostic biomarker [48]. The plasma-derived proteins ALB and TRANSF can be considered as indirect sign of subclinical inflammation as it occurs when there is an increase of protein leakage from inflamed conjunctival vessels [49][50][51]. They are usually present in a negligible amount in tears of normal subjects [26], and it has been shown that ALB increases whereas TRANSF decreases in moderate DED [27]; it is not clear why these proteins behave contrarily and if this may be due to blood-epithelial barrier functioning.…”

Human Tear Protein Analysis Using a Quantitative Microfluidic System: A Pilot Study

“…Results were displayed as gel-like image bands or as electropherogram peaks for each sample. Peaks in the protein profile were identified based on their molecular weight or mass (kDa) and the findings from previous studies, 4,5,7,12–15 and concentrations were obtained from the result page of the software.…”