Diurnal variation on tear stability and correlation with tear cytokine concentration.

PURPOSE: To investigate the effect of time of day on tear evaporation rate (TER) and tear break-up time, and its possible relationship with the concentration of inflammatory tear molecules (cytokines) in healthy subjects. METHODS: Participants with healthy ocular surfaces attended 3 visits, including the screening visit (V0), the 2nd visit (V1) and the 3rd visit (V2). There were 7-day intervals between visits. Participants with Dry Eye Disease (DED) were excluded by using appropriate clinical tests during V0. Clinical evaluation (TER and Non-Invasive Tear Break-Up Time (NITBUT)) and tear collection were performed during V1 and V2, between 9 and 10AM and 3-4PM. The relative humidity and temperature of the examination room were also measured. The tear fluid concentrations of 15 cytokines were measured by multiplex bead analysis. RESULTS: Seven men and 10 women (mean age ± S.D; 25.1 ± 6.63 years old) participated in the study. There were no differences in neither the TER and NITBUT outcomes, nor humidity and temperature among times or visits. Eleven out of the 15 cytokines measured were detectable in tear fluids in > 50% of the participants. In the tear levels, no significant (p > 0.05) inter- and/or intra-day differences were detected for EGF, fractalkine, IL-1RA, IL-1ß and IP-10. However, significant inter-day differences were found in the tear levels of IL-10 (p = 0.027), IFN-γ (p = 0.035) and TNF-α(p = 0.04) and intra-day differences in the tear levels of IL-8/CXCL8 (p = 0.034) and MCP-1 (p = 0.002). A significant correlation between TER and IL1-ß, IL-2, and Fractalkine (p = 0.03, p = 0.03 and p = 0.046, respectively) was found at V1. CONCLUSIONS: NITBUT and TER values had no significant variability over the course of a day (AM versus PM), or on different days in healthy participants when humidity and temperature were constant. However, some tear molecule levels did show inter- and intra-day variability, having an inconsistent and moderate correlation with TER diurnal variation.

Usefulness of a global rating change scale for contact lens discomfort evaluation.

OBJECTIVES: To evaluate the usefulness of a global rate of change scale (GRCS) to detect variations in contact lens discomfort (CLD). METHODS: Symptomatic contact lens (CL) wearers were recruited according to the 'Contact Lens Dry Eye Questionnaire-8' (CLDEQ-8). At the baseline visit, subjects scored their comfort following insertion of their habitual CL using a 0-100 visual analogue scale (VAS). After 4-10 h of CL wear, comfort was again self-evaluated with the VAS and with a GRCS (range, -50 to +50). Then, a daily disposable CL (DDCL) was fitted. After one month of DDCL wear, a follow-up visit was conducted where the same evaluations as the baseline visit were performed. Changes in comfort were estimated using a Student's t-test for normal variables and the Friedman test for multiple comparisons of non-parametric variables. Internal responsiveness was measured by calculating the standardised response mean. Agreement between scales was estimated by the intraclass correlation coefficient (ICC). RESULTS: Twenty-nine (22 females and 7 males) CL wearers with a mean age of 23.4 ± 5.4 years participated in the study. There was a significant decrease in comfort at both visits detected by the GRCS (baseline = -13.58 ± 17.48, p < 0.001; follow up = -6.86 ± 12.69, p = 0.007). However, the VAS did not detect that change, either at baseline (insertion = 64.28 ± 18.72 vs removal = 52.89 ± 17.64, p = 1.000) or follow-up visit (insertion = 81.97 ± 12.91 vs removal = 76.48 ± 16.02, p = 1.000). Comfort at insertion and removal times was significantly higher with the DDCL (p = 0.008 at insertion and p = 0.004 at removal). The standardised response mean was greater with the GRCS than the VAS at baseline (0.78 vs 0.63) and follow-up (0.54 vs 0.37) visits. Agreement between both scales was moderate and significant (p < 0.001) for both visits, ICC: 0.674 (95 % confidence interval (CI):0.411-0.833) (baseline) and 0.652 (95 % CI:0.377-0.821) (follow-up visit). CONCLUSIONS: The GRCS can detect slight changes in CL wear comfort and shows higher responsiveness than the VAS. This subjective scale can allow detection of changes in comfort in a simple and quick way.

Does placebo effect exist in contact lens discomfort management?

PURPOSE: To study the effect of daily disposable contact lens (DDCL) refitting in monthly contact lens (CL) wearers suffering from contact lens discomfort (CLD), and to assess if there is a placebo effect associated with this CLD intervention. METHODS: Symptomatic CL wearers, according to the Contact Lens Dry Eye Questionnaire 8 (CLDEQ-8 ≥ 12 points), were divided into two groups. The study group was provided with DDCLs (delefilcon A) and the control group with a masked pair of their habitual monthly CLs (placebo effect) and were assessed after one month. Then, the control group was provided with the same DDCLs and evaluated one month later. The symptoms were recorded with the CLDEQ-8 and global rating of change scale (GRCS). Non-invasive tear break-up time (NITBUT), conjunctival hyperaemia, fluorescein staining, and lid wiper epitheliopathy (LWE) were evaluated. Changes between visits, groups, and the effect of each intervention were analysed. RESULTS: Thirty-one participants (mean age: 23.2 ± 5.3 years) were recruited. The study group (n = 14) showed an improvement of -39.6 ± 25.8 % (p < 0.001) in CLDEQ-8 and 31.3 ± 14.6 points in GRCS (p < 0.001) after one month of DDCL use, while no changes in clinical tests were found. In the control group (n = 17), symptoms improved significantly after wearing the masked monthly CL (CLDEQ-8: -26.1 ± 31.0 %, p = 0.03; GRCS: 14.9 ± 17.0, p = 0.002), however a worsening in bulbar (26.5 ± 40.0 %; p = 0.02) and limbal hyperaemia (21.6 ± 34.7 %, p = 0.02) and an improvement of -19.1 ± 37.0 % (p = 0.049) in LWE was found. When the control group was fitted with the DDCL, improvements in GRCS (20.5 ± 25.5, p = 0.02), NITBUT (37.9 ± 42.3 %, p = 0.002), and conjunctival staining (-47.1 ± 59.9 %, p = 0.005) were noted. CONCLUSIONS: Refitting symptomatic monthly CL wearers with Delefilcon A DDCL is effective in reducing symptoms related to CLD. However, clinicians and researchers must be aware of the existence of a placebo effect when assessing the effectiveness of any CL refitting.

Contact Lens Discomfort Management: Outcomes of Common Interventions.

PURPOSE: To assess the consecutive implementation of habitual contact lens discomfort (CLD) management strategies: lid hygiene, daily disposable CL (DDCL) fitting, and artificial tear (AT) supplementation. METHODS: Contact lens (CL) wearers with CLD symptoms (CLDEQ-8 ≥12 points) were included in the study. Subjects with Meibomian gland dysfunction (MGD) were instructed to perform lid hygiene. All participants were fitted with a DDCL (delefilcon A) and evaluated 1 month later. After, half of them were randomly assigned to use AT (Povidone-2%) at least three times/day, and all participants were evaluated 1 month later. Tests performed were: lower tear meniscus area (LTMA), bulbar, limbal, and tarsal hyperemia, noninvasive tear break-up time (NITBUT), and corneal and conjunctival staining. Weighted combined clinical scores (CS) were created to analyze signs. Changes in symptoms (CLDEQ-8) and CS were analyzed using linear mixed models. RESULTS: Forty-two subjects (mean age: 23.2±4.9 years) completed the study. Two CS were created, CS 1 was composed of bulbar, limbal, and tarsal hyperemia and corneal staining, and CS 2 by NITBUT, LTMA, and conjunctival staining. CLDEQ-8 was reduced after lid hygiene (mean: -2.73±2.13; P=0.012) and DDCL use (mean: -10.1±3.54; P<0.01), but not after AT use (P=0.62). CS 1 did not change after any intervention. CS-2 was higher (P=0.04) in DGM subjects after lid hygiene, it decreased (P=0.04) after DDCL use. CONCLUSIONS: Lid hygiene is effective for reducing CLD symptoms in MGD patients. Refitting subjects with delefilcon A is an effective intervention for CLD to reduce symptoms and achieve a healthier ocular surface. Simultaneous administration of AT did not further improve CLD.

Topical Quercetin and Resveratrol Protect the Ocular Surface in Experimental Dry Eye Disease.

Purpose: To determine the anti-inflammatory effect of quercetin (QCT), resveratrol (RES), and their combination in a dry eye disease (DED) model. Methods: 0.01% QCT, 0.1% RES, 0.01% QCT + 0.1% RES (QCT + RES) or vehicle were topically applied in a desiccating stress (DS) mice model. CD4+ T cells isolated from DS-exposed mice were transferred to athymic recipient mice. Corneal fluorescein staining, tear production, and tear cytokine levels were evaluated in DS-exposed mice, and conjunctival CD4+ T cell infiltration was evaluated in recipient mice. Results: QCT (p < 0.001) and QCT + RES (p < 0.05) reduced corneal staining in DS-exposed mice. IL-1α tear concentration was reduced by QCT, RES, and QCT + RES (p < 0.05, 0.01 and 0.01, respectively) compared to DS + vehicle mice. CD4+ T cells increased in recipients of DS-exposed mice (p < 0.05) and were lower in recipients of QCT- and RES-treated mice (p < 0.05). Conclusion: The anti-inflammatory effect of QCT, RES, and QCT + RES on DED-experimental model suggests that their topical application could be used for DED treatment.

Corneal Sensitivity and Inflammatory Biomarkers in Contact Lens Discomfort.

PURPOSE: The aim of this study was to analyze whether symptoms of discomfort in hydrogel contact lens (HCL) wearers were associated with changes in corneal sensitivity or levels of tear inflammatory mediators. METHODS: Sixty-six subjects were included: 47 HCL wearers, further divided into 24 symptomatic and 23 asymptomatic wearers by the Contact Lens Dry Eye Questionnaire short form and 19 non-contact lens wearers. At least 24 h after HCL removal, we obtained scores from the Ocular Surface Disease Index and mechanical, hot, and cold corneal thresholds using a Belmonte esthesiometer. We collected 4 µl of tears with a capillary micropipette and measured levels of 12 inflammatory markers using a bead-based array: epidermal growth factor, fractalkine, interleukin-10 (IL-10), IL-1ß, IL-1 receptor antagonist, IL-2, IL-4, IL-6, IL-8, monocyte chemoattractant protein 1, tumor necrosis factor-α, and matrix metalloproteinase 9. RESULTS: There were no significant differences between groups in corneal sensitivity thresholds and levels of tear molecules. The following significant correlations were found in the total sample pooled: Ocular Surface Disease Index correlated with mechanical threshold (p < 0.01; rho = -0.324) and epidermal growth factor (p < 0.01, rho = -0.330), and mechanical threshold correlated with heat threshold (p < 0.01, rho = -0.321). CONCLUSIONS: Twenty-four hours after HCL removal, symptoms of discomfort in HCL wearers are not related to changes in corneal sensitivity or tear inflammatory mediator levels. This might indicate either that HCL wear has no effect on these parameters or that ocular surfaces recover from HCL-caused effects during the first hours after HCL removal. However, there were correlations for associations between symptoms, corneal sensitivity, and some molecules in tears.

Quercetin and Resveratrol Decrease the Inflammatory and Oxidative Responses in Human Ocular Surface Epithelial Cells.

PURPOSE: To determine the anti-inflammatory and antioxidant effects of quercetin (QCT) and/or resveratrol (RES) on human conjunctival (IOBA-NHC) and corneal (HCE) epithelial cell lines. METHODS: IOBA-NHC and HCE cells were treated with QCT (0.5-25 µM), RES (0.5-50 µM) and a low-dose mixture of QCT (0.5 µM) and RES (5 µM) (QCT+RES) and stimulated with either TNF-α or ultraviolet (UV)-B radiation. Cytokine production (IL-6, IL-8, IP-10, and VEGF) was analyzed by an immune bead-based array, and intracellular reactive oxygen species (ROS) production was determined by a H2DCF-DA dye assay. RESULTS: Stimulation of IOBA-NHC and HCE cells with TNF-α induced an increase of IL-6, IL-8, and IP-10 secretion in both cell lines. Quercetin and RES decreased IL-6 and IP-10 secretion in a dose-dependent manner in both cell lines. Interleukin-8 secretion was also inhibited in a dose-dependent manner by QCT in HCE, but only at 20 and 25 µM QCT and 50 µM RES in IOBA-NHC and at 50 µM RES in HCE. QCT+RES decreased IL-6 and IL-8 secretion (P < 0.01 and P < 0.05, respectively) in IOBA-NHC cells. Ultraviolet-B induced a significant increase of ROS in both cell lines (P < 0.01 and P < 0.001 for IOBA-NHC and HCE cells, respectively), which was significantly decreased in a dose-dependent manner by QCT and RES in HCE cells. Reactive oxygen species production in IOBA-NHC cells was inhibited (P < 0.05) by 50 µM RES. CONCLUSIONS: Quercetin and RES have anti-inflammatory and antioxidant effects on IOBA-NHC and HCE cells. These in vitro data suggest that both polyphenols may have a therapeutic potential in the treatment of inflammatory ocular surface diseases.

In Vitro Model for Predicting the Protective Effect of Ultraviolet-Blocking Contact Lens in Human Corneal Epithelial Cells.

PURPOSE: To develop an in vitro method to determine the protective effect of UV-blocking contact lenses (CLs) in human corneal epithelial (HCE) cells exposed to UV-B radiation. MATERIALS AND METHODS: SV-40-transformed HCE cells were covered with non-UV-blocking CL, UV-blocking CL or not covered, and exposed to UV-B radiation. As control, HCE cells were covered with both types of CLs or not covered, but not exposed to UV-B radiation. Cell viability at 24, 48 and 72 h, after UV-B exposure and removing CLs, was determined by alamarBlue(®) assay. Percentage of live, dead and apoptotic cells was also assessed by flow cytometry after 24 h of UV-B exposure. Intracellular reactive oxygen species (ROS) production after 1 h of exposure was assessed using the dye H(2)DCF-DA. RESULTS: Cell viability significantly decreased, apoptotic cells and intracellular ROS production significantly increased when UVB-exposed cells were covered with non-UV-blocking CL or not covered compared to non-irradiated cells. When cells were covered with UV-blocking CL, cell viability significantly increased and apoptotic cells and intracellular ROS production did not increase compared to exposed cells. CONCLUSIONS: UV-B radiation induces cell death by apoptosis, increases ROS production and decreases viable cells. UV-blocking CL is able to avoid these effects increasing cell viability and protecting HCE cells from apoptosis and ROS production induced by UV-B radiation. This in vitro model is an alternative to in vivo methods to determine the protective effect of UV-blocking ophthalmic biomaterials because it is a quicker, cheaper and reliable model that avoids the use of animals.