Molecular evidence for the role of inflammation in dry eye disease.

Ocular surface inflammation is propagated by a complex series of molecular processes and has been implicated in the pathogenesis of dry eye disease (DED), either as a causal or a downstream effect of ocular surface disease. A state of hyperosmolarity elicits an acute immune response in DED, leading to subsequent activation of the adaptive immune response. This cascade incites dysregulation of the immune system, triggering a vicious cycle of events that causes damage to the ocular surface. Symptoms associated with these events include burning, irritation, redness, photophobia and blurred vision. The chronic nature of the disease process can cause permanent alterations to the ocular surface and adnexa. An increasing investment in treatment options, and positive outcomes with novel therapies that have received subsequent regulatory approval, lends further support to the role of inflammation in DED. This review highlights the nature and function of a range of fundamental inflammatory molecules in DED to provide the clinician with an appreciation for the ways in which these factors might be manipulated in DED management.

Use of a Purpose-Built Impression Cytology Device for Gene Expression Quantification at the Ocular Surface Using Quantitative PCR and Droplet Digital PCR.

PURPOSE: To describe an impression cytology (IC) technique using a purpose-built, sterile, EYEPRIM IC device that can be coupled with a TRIzol reagent-based RNA extraction protocol to yield sufficient RNA for gene expression analysis. METHODS: IC samples using the EYEPRIM device were collected from the bulbar conjunctiva, with and without topical anesthesia, and evaluated for RNA yield, the absence of polymerase chain reaction (PCR) inhibitors, and the ability to detect biomarkers by quantitative real-time PCR and droplet digital PCR. A technique for collecting IC samples in the clinic, while preserving RNA, and a protocol for subsequent laboratory analysis of RNA were developed. RESULTS: The extracted RNA was free of PCR inhibitors and could be synthesized into complementary DNA and used for successful relative quantification of ocular surface biomarkers by quantitative real-time PCR. For gene targets present in low abundance, complementary DNA could also be used for quantification by the relatively new and emerging method of droplet digital PCR. The described method was successfully used to evaluate 3 biomarkers in a clinical trial assessing the tolerability of a proprietary eyelid therapy in 92 IC samples from a study population of 46 participants. CONCLUSIONS: IC is a recognized technique for ocular surface cell evaluation and protein biomarker quantification but is infrequently used for quantifying gene expression. The EYEPRIM device allows ease of use and impression-to-impression consistency while accurate gene expression data offers a highly specific and sensitive method of disease characterization for clinician scientists to use in diagnosis.

Randomised masked trial of the clinical safety and tolerability of MGO Manuka Honey eye cream for the management of blepharitis.

OBJECTIVE: To assess the clinical safety and tolerability of a novel MGO Manuka Honey microemulsion (MHME) eye cream for the management of blepharitis in human subjects. METHODS AND ANALYSIS: Twenty-five healthy subjects were enrolled in a prospective, randomised, paired-eye, investigator-masked trial. The MHME eye cream (Manuka Health New Zealand) was applied to the closed eyelids of one eye (randomised) overnight for 2 weeks. LogMAR visual acuity, eyelid irritation symptoms, ocular surface characteristics and tear film parameters were assessed at baseline, day 7 and day 14. Expression of markers of ocular surface inflammation (matrix metalloproteinase-9 and interleukin-6) and goblet cell function (MUC5AC) were quantified using impression cytology at baseline and day 14. RESULTS: There were no significant changes in visual acuity, eyelid irritation symptoms, ocular surface characteristics, tear film parameters and inflammatory marker expression during the 2-week treatment period in treated and control eyes (all p>0.05), and measurements did not differ significantly between eyes (all p>0.05). No major adverse events were reported. Two subjects experienced transient ocular stinging, presumably due to migration of the product into the eye, which resolved following aqueous irrigation. CONCLUSION: The MHME eye cream application was found to be well tolerated in healthy human subjects and was not associated with changes in visual acuity, ocular surface characteristics, tear film parameters, expression of markers of inflammation or goblet cell function. The findings support future clinical efficacy trials in patients with blepharitis. TRIAL REGISTRATION NUMBER: ACTRN12616000540415.

Compatibility of phospholipid liposomal spray with silicone hydrogel contact lens wear.

PURPOSE: To assess the effects of two weeks of regular phospholipid liposomal spray application on lipid layer grade, tear film stability, subjective comfort, visual acuity, and lipid deposition in silicone hydrogel contact lens wearers. METHODS: Thirty-one existing contact lens wearers were enrolled and fitted with two week planned replacement silicone hydrogel contact lenses (Acuvue® Oasys®) in a prospective, randomized, paired-eye, investigator-masked trial. A phospholipid liposomal spray (Tears Again®) was applied to one eye (randomized) four times daily for two weeks. LogMAR high contrast visual acuity (VA), low contrast glare acuity (LCGA), non-invasive tear film break-up time (NIBUT), and lipid layer grade (LLG) were measured at baseline and day 14, in both treated and control eyes. Subjective comfort relative to baseline, and spectrofluorophotometric assessment of contact lens surface lipid deposition were also assessed on day 14. RESULTS: All measurements did not differ at baseline between treated and control eyes. Lipid layer thickness and tear film stability were increased on day 14 in treated eyes (all p<0.05), but not in control eyes (all p>0.05). A greater proportion of participants reported improved comfort in the treated eye relative to the control eye (p=0.002). There were no significant differences in visual acuity or in contact lens surface lipid deposition, between treated and control eyes, on day 14 (all p>0.05). CONCLUSION: The phospholipid liposomal spray increased tear film stability, lipid layer thickness and subjective comfort in silicone hydrogel contact lens wearers, without adversely affecting visual acuity or contact lens surface lipid deposition.