Tear film inflammatory cytokine upregulation in contact lens discomfort.
PURPOSE
To investigate the ocular inflammatory response, using clinical and immunological techniques, in people experiencing contact lens (CL) discomfort.


METHODS
This study involved 38 adults who were full-time, silicone-hydrogel CL wearers. Participants were categorized into groups based upon a validated CL dry-eye questionnaire (CLDEQ-8) (n = 17 'asymptomatic', CLDEQ-8 score <9; n = 21 'symptomatic', CLDEQ-8 score ≥13). Examinations were performed at two visits (one with, and one without, CL wear), separated by one-week. Testing included: tear osmolarity, ocular redness, tear stability, ocular surface staining, meibography, tear production and tear collection. Tear osmolarity was taken from the inferior-lateral and superior-lateral menisci. The 'Inferior-Superior Osmotic Difference', I-SOD, was the absolute osmolarity difference between these menisci. Concentrations of seven cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-gamma, TNF-alpha) were assayed from basal tears using multiplex cytometric bead array.


RESULTS
At baseline, there was no significant difference in key clinical signs between asymptomatic and symptomatic CL wearers (p > 0.05). The I-SOD was greater in symptomatic than asymptomatic CL wearers (23.1 ± 2.6 versus 11.3 ± 1.4 mOsmol/L, p = 0.001). People experiencing CL discomfort had higher tear IL-17A (122.6 ± 23.7 versus 44.0 ± 10.0 pg/mL, p = 0.02) and reduced tear stability (6.3 ± 1.1 versus 10.4 ± 1.6 s, p = 0.03) after several hours of CL wear. Tear IL-17A levels correlated with both the I-SOD (r = 0.43, p = 0.01) and CLDEQ-8 score (r = 0.40, p = 0.01).


CONCLUSIONS
CL discomfort occurs in individuals having no clinical dry eye signs, and is associated with higher tear levels of the pro-inflammatory cytokine IL-17A. These findings support an association between the discomfort response and low-grade, ocular surface inflammation.
['Gad|Anne|A|', 'Vingrys|Algis Jonas|AJ|', 'Wong|Chinn Yi|CY|', 'Jackson|David Charles|DC|', 'Downie|Laura Elizabeth|LE|']
D000328:Adult D003228:Conjunctiva D003263:Contact Lenses, Hydrophilic D016207:Cytokines D015352:Dry Eye Syndromes D005260:Female D006801:Humans D007249:Inflammation D008297:Male D009994:Osmolar Concentration D013666:Tears D015854:Up-Regulation
Tear film Cytokine Contact lens Contact lens discomfort Ocular surface IL-17A Inflammation Interleukin