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K. M. Haworth, J. J. Nichols, M. Thangavelu, L. Sinnott, H. L. Chandler, K. K. Nichols; Examination of Human Meibum Collection and Extraction Techniques. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2544.
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© ARVO (1962-2015); The Authors (2016-present)
To compare various meibum collection methods and extraction techniques.
A total of 40 subjects were seen on two visits separated by 14 days (two-thirds were non-dry eye, and one-third dry eye). Meibum was collected from the right eye with a glass microcapillary tube, and either a Dacron swab or a cytology microbrush was used for collection from the left eye. Extraction was performed using 2:1 chloroform:methanol solvent for 15 minutes, which was done either immediately (samples from visit 2) or after up to three months later (those from visit 1). All meibum samples were stored frozen at -80o C until analysis. Analysis of total lipids and inorganic phosphates (e.g., phospholipids) of individual patient samples was conducted via 96 well microtiter plate assay based techniques. The effect of collection method, extraction, and dry eye status was examined using repeated measures ANOVA (for total lipid) and logistic regression (for inorganic phosphates).
Analysis of total lipid showed statistical significance for the collection device (p<0.0001), a trend for dry eye status (p=0.13), but no impact of extraction technique (p=0.98). Relative to the glass microcapillary tube, the cytology microbrush yielded on average 1.09 µg more total lipid (p=0.0002), while the Dacron swab yielded 4.50 µg more total lipid (p<0.0001).
Greater than 60% of meibum samples yielded inorganic phosphate values of zero. Of meibum samples with inorganic phosphates present, statistical analysis showed each of all three predictors to be statistically significant. Odds ratio estimates showed the immediate extraction (p<0.0001), glass microcapillary tube compared to Dacron swab (p=0.003), and non-dry eye (p=0.02) to be associated with the greater likelihood of detection of inorganic phosphates. For combined predictor levels, the probability of finding inorganic phosphates was highest using cytology microbrush collection with immediate extraction.
Total lipid collection was highest by Dacron swab collection. Highest probability of inorganic phosphate detection was accomplished using cytology microbrush collection with immediate extraction.
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