Purchase this article with an account.
Cameron K Postnikoff, Carrie E Huisingh, Gerald McGwin, Kelly K Nichols; Variation of the leukocyte composition in the open eye of normal and dry eye subjects. Invest. Ophthalmol. Vis. Sci. 2017;58(8):491.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The closed eye is characterized by a large neutrophil influx, but little is known about the presence or absence of leukocytes in the awake, open eye tear film. This study sought to compare normal subjects and dry eye subjects for daily variation in open eye leukocyte composition.
Nine normals and six dry eye subjects were enrolled, with a combined average age of 32 years, and subjects were 70% female. Dry eye subjects were recruited based upon a prior diagnosis of dry eye disease, and were not taking any ocular medications. Subjects were trained for self-collection of leukocytes using a gentle wash of the ocular surface, using 5 mL of phosphate buffered saline per eye. Subjects collected tears at four different time points across four separate days: at awakening, between 8-9am, between 11am-12pm, and between 4-5pm. Tear samples were processed and leukocytes were counted using a Moxi Z cell counter. Samples were then stained with CD45 and a fixable viability stain to confirm the presence of neutrophils or lymphocytes based on CD45+ staining and forward scatter/side scatter sample characteristics. General linear models using generalized estimating equations were used.
Subjects had been awake for 2.5±0.9, 5.2±1.22, and 9.9±0.99 hours, at the 8am, 11am, and 4pm collections, respectively. Overall, roughly 813,000 cells were collected after a full night of sleep. At 8am, 11am, and 4pm, the total average number of recovered cells from normals was 6,266, 14,142, and 14,048, and dry eye subjects was 5,913, 8,558, and 11,914, respectively, as measured by the Moxi Z cell counter. Overall, there were significantly fewer leukocytes in the open eye versus the closed eye (at awakening) (p<0.001), but there was no difference between the open eye time points (p=0.21). There was no statistically significant difference between normals and dry eye subjects in terms of leukocyte recovery in the open eye (p=0.83). Flow cytometry demonstrated the presence of both neutrophils and lymphocytes, but yields were too low for phenotypic analysis.
Within two and a half hours of eye opening, closed eye leukocytes are rapidly cleared from the ocular surface. However, the open eye tear film does contain a tonic level of both neutrophils and lymphocytes, both in normal and dry eye subjects, which may play a role in ocular surface homeostasis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only