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Updated: Aug 30, 2026
Impression Cytology of the Lid Wiper Area
Published on: August 9, 2016
Clinical appearance and microscopic analysis of mucin balls associated with contact lens wear
Thomas J Millar1, Eric B Papas, Jerome Ozkan
1School of Science Food and Horticulture, University of Western Sydney, NSW, Australia. t.millar@uws.edu.au
Purpose:
The structure of mucin balls collected from silicone hydrogel contact lens wearers was examined to determine their nature.
Methods:
Tears containing mucin balls were collected using a capillary tube. These were processed for light microscopic histochemistry, scanning electron microscopy, and electron microscopic elemental analysis. Mucin balls were also observed in vivo using confocal microscopy.
Results:
Histology showed that the mucin balls were PAS positive, indicating that glycoproteins form a major component. Lipids and bacteria were not detected. Scanning electron microscopy did not show the surface to be smooth but revealed a variation in density across the surface. Elemental analysis was inconclusive.
Conclusions:
Mucin balls are likely to be made from collapsed mucin and are unlikely to have been formed as a result of pearling around a silicon, lipid, or bacterial kernel.
