Ocular Surface Immune Cell Profiles in Contact Lens–Induced Discomfort

PURPOSE: Contact lens–induced discomfort (CLD) remains a primary factor in discontinuation or prevention of contact lens wear. Thus, we investigated the role of ocular surface immune cells in subjects with CLD. METHODS: Habitual contact lens (CL) wearers with CLD (n = 19; 38 eyes) and without CLD (n = 21; 42 eyes) as determined by the Contact Lens Dry Eye Questionnaire-8 was included in a trial. Enrolled subjects used either of the two types of CL (designated as CL-A or CL-D). Ocular surface cells from the bulbar conjunctiva were obtained by impression cytology. The collected cells were phenotyped using fluorochrome-conjugated antibodies specific for leukocytes (CD45(+)), neutrophils (CD66b(+,High,Low)), macrophages (CD163(+)), T cells (CD3(+)CD4(+), CD3(+)CD8(+)), natural killer (NK) cells (CD56(+, High, Low)), natural killer T (NKT) cells (CD3(+)CD56(+)), and gamma delta T (γδT) cells (CD3(+)γδTCR(+)) by flow cytometry. Further, corneal dendritic cell density (cDCD) was also determined using in vivo confocal microscopy. RESULTS: Significantly higher proportions of CD45(+) cells were observed in subjects with CLD compared to those without CLD. The percentages of CD66b(Total,Low), CD163(+), pan T cells, CD4(+)T cells, CD8(+)T cells, CD56(Total,High,Low) (NK) cells, and NKT cells, as well as the CD4/CD8 ratio, were significantly higher in CLD subjects. The proportion of T cells (CD4, CD8, CD4/CD8 ratio, NKT cells) and macrophages exhibited a direct association with discomfort score. The percentages of CD45(+), CD66b(Total,Low), CD163(+), CD3(+), CD56(Total,High,Low), and NKT cells and cDCD were significantly higher in CLD subjects wearing CL-D. The percentages of CD66b(High), CD4(+)T cells, CD8(+)T cells, NKT cells, and CD4/CD8 ratio were significantly higher in CLD subjects wearing CL-A. CONCLUSIONS: Increased proportions of ocular surface immune cells are observed in CLD, and the lens type could impact the immune cells associated with CLD. TRANSLATIONAL RELEVANCE: The association between the proportion of altered ocular surface immune cell subsets and contact lens–induced discomfort underpins the importance of considering immune-related aspects during contact lens development and in the clinical management of ocular surface pain.