Gene expression changes in conjunctival cells associated with contact lens wear and discomfort.

PURPOSE: This study aimed to analyze the differences in the expression of pain-related genes in conjunctival epithelial cells among symptomatic contact lens (CL) wearers (SCLWs), asymptomatic CL wearers (ACLWs), and non-CL wearers (non-CLWs). METHODS: For this study, 60 participants (20 non-CLWs, 40 CLWs) were enrolled. The CLW group comprised 20 ACLWs and 20 SCLWs according to the Contact Lens Dry Eye Questionnaire short form©. Conjunctival cells were collected using impression cytology, and RNA was isolated and used to determine the expression levels of 85 human genes involved in neuropathic and inflammatory pain. The effects of CL wear and discomfort were evaluated using mixed-effects ANOVA with partially nested fixed-effects model. Gene set enrichment analysis was performed to assign biological meaning to sets of differentially expressed genes. RESULTS: Six genes (CD200, EDN1, GRIN1, PTGS1, P2RX7, and TNF) were significantly upregulated in CLWs compared to non-CLWs. Eleven genes (ADORA1, BDKRB1, CACNA1B, DBH, GRIN1, GRM1, HTR1A, PDYN, PTGS1, P2RX3, and TNF) were downregulated in SCLWs compared to ACLWs. These genes were mainly related to pain, synaptic transmission and signaling, ion transport, calcium transport and concentration, and cell-cell signaling. CONCLUSIONS: CL wear modified the expression of pain- and inflammation-related genes in conjunctival epithelial cells. These changes may be in part, along with other mechanisms, responsible for CL discomfort in SCLWs.

Effect of a single vectored thermal pulsation treatment of Meibomian gland dysfunction patients under controlled environmental conditions.

To assess the prophylactic effect of LipiFlow treatment in Meibomian gland dysfunction (MGD) patients exposed to an adverse environmental humidity. MGD patients were exposed to normal (23 °C; 50% relative humidity; 30 min) and adverse (23 °C; 10% relative humidity; 2 h) controlled environments consecutively during baseline and follow-up visits (3, 6, and 12 months) after a single LipiFlow treatment. Ocular Surface Disease Index (OSDI), lipid layer thickness (LLT), fluorescein tear break-up time (TBUT), corneal and conjunctival staining, change in dry eye symptoms questionnaire (CDES-Q), and Meibomian gland yielding liquid secretion (MGYLS), were assessed. Linear mixed-effects and cumulative logit mixed models were fitted to assess the effect of the LipiFlow treatment over time and within the controlled environments. Seventeen females and 4 males (59.6 ± 9.4 years) completed the study. LLT and TBUT did not vary significantly (p > 0.05) after LipiFlow treatment. OSDI, corneal and conjunctival staining, and MGYLS scores were improved (p ≤ 0.01) 12 months after treatment. After the adverse exposure, corneal staining increased at all visits (p = 0.01), and there was no significant improvement in CDES-Q scores after LipiFlow treatment (p ≥ 0.07). One LipiFlow treatment improved objective and subjective outcomes in MGD disease for at least one year. Further studies are needed to support that LipiFlow might also help as an adjuvant to avoid acute flares against an adverse environmental humidity.