Recovery of meibomian oil after lid margin cleansing, studied by meibometry in normal individuals.

Abstract

Abstract: : Purpose: To evaluate meibomian oil recovery after lid margin cleansing, in normal individuals, using scanning meibometry (SM). With this novel technique the full profile of a lid margin oil blot is imaged with a flat–bed scanner and assessed by densitometry. Methods: 41 volunteers participated, (25 male, 16 female; mean age 22.9, range 18–29), with no evidence of meibomian gland dysfunction. Following topical anaesthesia, lower and upper lid margins were cleansed of oil, using a cotton–tip applicator soaked in hexane. Baseline meibomian oil levels from the central lower lid margin were measured immediatelyy, (time zero), and recovery was measured at 10 minutes on the left lower lid and at 20 minutes on the right. The system was calibrated to allow conversion of Sscan values were converted into equivalent lipid values. Results:Mean casual levels for the group were 3.61 µ g/ mm² (SD ± 0.73 µ g/mm², range 1.76–4.90 µ g/ mm². Baseline levels above an arbitrary value of 0.725 µ g/mm², were taken to imply inadequate cleansing and were excluded from further study. Mean meibomian oil recovery was 1.06 µ g/ mm² (SD ± 0.95 µ g/ mm²) at 10 minutes and 1.54 µ g/ mm² (SD ± 1.26 µ g/ mm²) at 20 minutes. This represented 27% (95% confidence intervals (CI): 23–30%) and 41% (95% CI: 34–47%) of the casual level, respectively. For the group, oil levels at 20 min = 0.96x (oil level at 10min)+0.27 µ g/ mm², r²=0.7). There was considerable scatter in the data, with a proportion of subjects showing a lower lipid recovery at 20 than at 10 minutes. Conclusions:For the group as a whole, the data indicated that recovery was similar at the two time points, suggesting that the lid margin reservoirs fill rapidly at first, (ie within 10 minutes), and then more slowly, to reach a steady–state beyond the time frame of the study.

Keywords: cornea: tears/tear film/dry eye • lipids