The purpose of this study was to count and analyze the white blood cells in tear samples collected from study participants following sleep. The results from contact lens wearers were compared with the results from non-contact lens wearers.
The objective of the study was to determine and compare the relative oxidative response of polymorphonuclear neutrophils (PMNs), the relative cell adhesion response of PMNs, and the leukocyte population in tear samples collected from contact lens wearers and non-contact lens wearers. Tear samples were collected via a binocular eye-wash. The samples were processed, and a cell count was performed using a hemacytometer. Flow cytometry was used to determine the expression of different PMN cell markers before and after stimulation with bacterial lipopolysaccharide (LPS).
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
65
Commercially marketed, silicone hydrogel, single-vision contact lens FDA-approved for daily and extended (overnight) wear for up to 30 nights.
Commercially marketed, silicone hydrogel, single-vision contact lens FDA-approved for daily or extended (overnight) wear up to 6 nights.
Hydrogen peroxide-based contact lens care system for nightly cleaning and disinfection of study lenses
University of Waterloo Centre for Contact Lens Research
Waterloo, Ontario, Canada
Leukocyte Population
A tear sample was collected after 8 hours of sleep using an ocular surface cell collection apparatus (OSCCA). Different types of white blood cells (leukocytes) were identified, which included neutrophils, monocytes, and lymphocytes. The total amount of leukocytes for contact lens wearers and non-lens wearers is presented. Potential differences in leukocyte count between lens wearers and non-lens wearers may indicate a different immune response.
Time frame: Week 5
Relative Cell Adhesion Response of Polymorphonuclear Leukocytes (PMNs)
A tear sample was collected after 8 hours of sleep using an ocular surface cell collection apparatus (OSCCA) and analyzed on a flow cytometer. CD54 is a protein typically found in the cell membrane of leukocytes, which up-regulates during inflammation and promotes cell adhesion. Cell adhesion response is reported as a ratio of stimulated to non-stimulated samples.
Time frame: Week 5
Relative Oxidative Response of Polymorphonuclear Leukocytes (PMNs)
A tear sample was collected after 8 hours of sleep using an ocular surface cell collection apparatus (OSCCA) and analyzed on a flow cytometer. Oxidative response is reported as a ratio of activated to non-activated samples. DCF (dichlorofluorescein diacetate) is a molecular probe that measures the oxidative burst. Upon stimulation, the PMNs synthesize reactive oxygen species, such as superoxide or hydrogen peroxide, which is detected by the probe. Differences in the oxidative response between contact lens wearers and non-lens wearers is indicated by a shift in the ratio (stimulated/unstimulated).
Time frame: Week 5
Change From Week 1 in Leukocyte Population at Week 5
A tear sample was collected after 8 hours of sleep using an ocular surface cell collection apparatus (OSCCA). Different types of white blood cells (leukocytes) were identified, which included neutrophils, monocytes, and lymphocytes. The difference between total leukocytes for contact lens wearers and non-lens wearers (Week 5 minus Week 1) is presented.
Time frame: Week 1, Week 5
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Change From 1 Week in Relative Cell Adhesion Response of PMNs at Week 5
A tear sample was collected after 8 hours of sleep using an ocular surface cell collection apparatus (OSCCA) and analyzed on a flow cytometer. Cell adhesion response is reported as a ratio of activated to non-activated samples. The difference between the ratio data for contact lens wearers and non-lens wearers (Week 5 minus Week 1) is presented.
Time frame: Week 1, Week 5
Change From Week 1 in Relative Oxidative Response of PMNs at Week 5
A tear sample was collected after 8 hours of sleep using an ocular surface cell collection apparatus (OSCCA) and analyzed on a flow cytometer. Oxidative response is reported as a ratio of activated to non-activated samples. The difference between the ratio data for contact lens wearers and non-lens wearers (Week 5 minus Week 1) is presented.
Time frame: Week 1, Week 5