Expanded biochemical analyses of human tear fluid: Polyvalent faces of the schirmer strip.

The tear film forms a protective barrier between the ocular surface and the external environment. Despite its small volume, recent advancements in preanalytical and analytical procedures have enabled its in-depth analysis using multiple approaches. However, the diversity of tear film collection methods and the lack of standardization in pre-analytical methods represent the main obstacles to reproducible results and comparison among different studies. In this study, we first improved the pre-analytical procedures for the extraction of various molecular entities from Schirmer strips (ScS). Subsequently, our investigation focused on analyzing the molecular variances that might occur between two primary tear collection methods: capillary tube (CT) and ScS. Additionally, we examined different parts of the ScS to underscore these variations, which could serve as crucial factors for developing a standardized, optimized protocol for sample processing. Our results show that the inclusion of surfactants in the extraction process enhanced both the yield of protein extraction and the number of proteins identified in ScS, by effectively lysing the cells and improving the solubility of several intracellular proteins. In addition to proteins, nucleic acids could also be recovered for gene expression analyses, particularly from the bulb region of the ScS which is placed in the cul-de-sac. Despite their diluted nature, extracts from ScS remain a suitable material for retrieving tear proteins such as IL-17A at levels as low as the fg/mL range, thanks to highly sensitive immunoassays. Collection methods can affect measured tear protein levels. Lactoferrin is found in higher percentages in capillary electrophoresis analysis of tears collected using ScS compared to tears collected by CT (39.6 ± 4.8% versus 31 ± 4.4%).

Evaluation of neuroprotective and immunomodulatory properties of mesenchymal stem cells in an ex vivo retinal explant model.

BACKGROUND: Glaucoma is a blinding degenerative neuropathy in which the death of retinal ganglion cells (RGCs) causes progressive loss of visual field and eventually vision. Neuroinflammation appears to be a key event in the progression and spread of this disease. Thus, microglial immunomodulation represents a promising therapeutic approach in which mesenchymal stem cells (MSCs) might play a crucial role. Their neuroprotective and regenerative potentials have already raised hope in animal models. Yet no definitive treatment has been developed, and some safety concerns have been reported in human trials. In the present study, we investigated the neuroprotective and immunomodulatory properties as well as the safety of MSCs in an ex vivo neuroretina explant model. METHODS: Labeled rat bone marrow MSCs were placed in coculture with rat retinal explants after optic nerve axotomy. We analyzed the neuroprotective effect of MSCs on RGC survival by immunofluorescence using RBPMS, Brn3a, and NeuN markers. Gliosis and retinal microglial activation were measured by using GFAP, CD68, and ITGAM mRNA quantification and GFAP, CD68, and Iba1 immunofluorescence stainings. We also analyzed the mRNA expression of both 'M1' or classically activated state inflammatory cytokines (TNFα, IL1ß, and IL6), and 'M2' or alternatively activated state microglial markers (Arginase 1, IL10, CD163, and TNFAIP6). RESULTS: The number of RGCs was significantly higher in retinal explants cultured with MSCs compared to the control group at Day 7 following the optic nerve axotomy. Retinal explants cultured with MSCs showed a decrease in mRNA markers of gliosis and microglial activations, and immunostainings revealed that GFAP, Iba1, and CD68 were limited to the inner layers of the retina compared to controls in which microglial activation was observed throughout the retina. In addition, MSCs inhibited the M1 phenotype of the microglia. However, edema of the explants was observed in presence of MSCs, with an increase in fibronectin labeling at the surface of the explant corresponding to an epiretinal membrane-like phenotype. CONCLUSION: Using an ex vivo neuroretina model, we demonstrated a neuroprotective and immunomodulatory effect of MSCs on RGCs. Unfortunately, the presence of MSCs also led to explant edema and epiretinal membrane formation, as described in human trials. Using the MSC secretome might offer the beneficial effects of MSCs without their potential adverse effects, through paracrine signaling.

Effect of artificial tears on dynamic optical quality in patients with dry eye disease.

BACKGROUND: In clinical practice, fluctuating vision or decreased quality of vision is a common complaint in DED patients. Our study was designed to investigate the change in dynamic optical quality in dry eye patients after the use of artificial tears. METHODS: Fifty-nine patients with dry eye disease (DED) and 31 control subjects were included in this prospective case-control study. There was no significant difference in age and sex between these two groups (P = 0.342, P = 0.847, respectively). Clinical evaluation of the ocular surface included Ocular Surface Disease Index (OSDI), tear film break-up time (TBUT), lipid layer thickness (LLT), and Schirmer I test. DED patients were divided into two groups, mild (31 patients) and severe (28 patients). The optical quality of the tear film was measured with the Optical Quality Analysis System (OQAS) using the mean objective scatter index (mean OSI), standard deviation of objective scatter index (SD-OSI) and modulation transfer function cut-off (MTF cut-off). After baseline examinations, one drop of artificial tears (ATs, carboxymethylcellulose ophthalmic solution, 0.5%) was instilled in both eyes, and optical quality parameters were measured again at 5 and 30 min following application of ATs. RESULTS: At baseline, the mean OSI was higher in the DED group (0.95 ± 0.54) than in controls (0.54 ± 0.23, P < 0.001). The SD-OSI was also significantly increased in DED patients (0.44 ± 0.71) compared to control subjects (0.12 ± 0.06, P = 0.003). Five minutes after AT instillation, mean OSI and SD-OSI decreased significantly in severe DED patients (P = 0.044; P = 0.018), remained unchanged in mild DED patients, and increased in the control group (P = 0.019; P < 0.001). Thirty minutes after AT instillation, no significant difference in optical quality parameters was observed among the three groups. CONCLUSION: The effect of ATs on optical quality in patients with DED may differ according to the severity of the disease. Measurement of optical quality might be a promising tool to evaluate the effects of various ATs and possibly individualize treatment in DED patients.

An overview of current alternative models in the context of ocular surface toxicity.

The 21st century has seen a steadily increasing social awareness of animal suffering, with increased attention to ethical considerations. Developing new integrated approaches to testing and assessment (IATA) strategies is an Organisation for Economic Co-operation and Development (OECD) goal to reduce animal testing. Currently, there is a lack of alternative models to test for ocular surface toxicity (aside from irritation) in lieu of the Draize eye irritation test (OECD guideline No. 405) performed in rabbits. Five alternative in vitro or ex vivo methods have been validated to replace this reference test, but only in combination. However, pathologies like Toxicity-Induced Dry Eye (TIDE), cataract, glaucoma, and neuropathic pain can occur after exposure to a pharmaceutical product or chemical and therefore need to be anticipated. To do so, new models of lacrimal glands, lens, and neurons innervating epithelia are required. These models must take into account real-life exposure (dose, time, and tear film clearance). The scientific community is working hard to develop new, robust, alternative, in silico, and in vitro models, while attempting to balance ethics and availability of biological materials. This review provides a broad overview of the validated methods for analyzing ocular irritation and those still used by some industries, as well as promising models that need to be optimized according to the OECD. Finally, we give an overview of recently developed innovative models, which could become new tools in the evaluation of ocular surface toxicity within the scope of IATAs.

Driving behaviour and visual compensation in glaucoma patients: Evaluation on a driving simulator.

BACKGROUND: To assess the driving performance and both the visual scanning and driving compensations of glaucoma patients. METHODS: In this case-control pilot study, the driving behaviour and performance of 14 patients with glaucoma and nine healthy age- and sex-similar control subjects were compared in a fixed-base driving simulator. All subjects performed in four scenarios with one to two hazardous situations on urban streets, for a total of five hazards. Measurements taken during the tests included reaction times, longitudinal regulation, lateral control and eye and head movements. RESULTS: Glaucoma patients showed poor driving performance with longer reaction time to hazardous situations than control subjects: pedestrians crossing the road from the left (p < 0.022) or from the right (p = 0.013), and vehicles coming from the left (p = 0.002). Their mean duration of lateral excursion was longer (p = 0.045), and they showed more lane excursions in a wide left curve (p = 0.045). Glaucoma patients also showed a higher standard deviation of time-headway (p = 0.048) with preceding vehicles. Analyses of driving behavioural compensations on curved roads showed that glaucoma patients stayed closer to the centre line in large (p = 0.006) and small (p = 0.025) left curves and on small right curves (p = 0.041). Additionally, on straight roads, as compared to control subjects, glaucoma patients showed longer mean time-headway (p = 0.032) and lower mean speed (p = 0.04). Finally, the glaucoma group exhibited a larger standard deviation of horizontal gaze (p = 0.034) than the control subjects. CONCLUSIONS: In a virtual driving environment, glaucoma patients exhibited unsafe driving behaviours, despite their driving and eye-scanning compensations.

Shhedding New Light on the Role of Hedgehog Signaling in Corneal Wound Healing.

The cornea, an anterior ocular tissue that notably serves to protect the eye from external insults and refract light, requires constant epithelium renewal and efficient healing following injury to maintain ocular homeostasis. Although several key cell populations and molecular pathways implicated in corneal wound healing have already been thoroughly investigated, insufficient/impaired or excessive corneal wound healing remains a major clinical issue in ophthalmology, and new avenues of research are still needed to further improve corneal wound healing. Because of its implication in numerous cellular/tissular homeostatic processes and oxidative stress, there is growing evidence of the role of Hedgehog signaling pathway in physiological and pathological corneal wound healing. Reviewing current scientific evidence, Hedgehog signaling and its effectors participate in corneal wound healing mainly at the level of the corneal and limbal epithelium, where Sonic Hedgehog-mediated signaling promotes limbal stem cell proliferation and corneal epithelial cell proliferation and migration following corneal injury. Hedgehog signaling could also participate in corneal epithelial barrier homeostasis and in pathological corneal healing such as corneal injury-related neovascularization. By gaining a better understanding of the role of this double-edged sword in physiological and pathological corneal wound healing, fascinating new research avenues and therapeutic strategies will undoubtedly emerge.

Capsazepine decreases corneal pain syndrome in severe dry eye disease.

BACKGROUND: Dry eye disease (DED) is a multifactorial disease of the ocular surface accompanied by neurosensory abnormalities. Here, we evaluated the effectiveness of transient receptor potential vanilloid-1 (TRPV1) blockade to alleviate ocular pain, neuroinflammation, and anxiety-like behavior associated with severe DED. METHODS: Chronic DED was induced by unilateral excision of the Harderian and extraorbital lacrimal glands of adult male mice. Investigations were conducted at 21 days after surgery. The mRNA levels of TRPV1, transient receptor potential ankyrin-1 (TRPA1), and acid-sensing ion channels 1 and 3 (ASIC1 and ASIC3) in the trigeminal ganglion (TG) were evaluated by RNAscope in situ hybridization. Multi-unit extracellular recording of ciliary nerve fiber activity was used to monitor spontaneous and stimulated (cold, heat, and acid) corneal nerve responsiveness in ex vivo eye preparations. DED mice received topical instillations of the TRPV1 antagonist (capsazepine) twice a day for 2 weeks from d7 to d21 after surgery. The expression of genes involved in neuropathic and inflammatory pain was evaluated in the TG using a global genomic approach. Chemical and mechanical corneal nociception and spontaneous ocular pain were monitored. Finally, anxiety-like behaviors were assessed by elevated plus maze and black and white box tests. RESULTS: First, in situ hybridization showed DED to trigger upregulation of TRPV1, TRPA1, ASIC1, and ASIC3 mRNA in the ophthalmic branch of the TG. DED also induced overexpression of genes involved in neuropathic and inflammatory pain in the TG. Repeated instillations of capsazepine reduced corneal polymodal responsiveness to heat, cold, and acidic stimulation in ex vivo eye preparations. Consistent with these findings, chronic capsazepine instillation inhibited the upregulation of genes involved in neuropathic and inflammatory pain in the TG of DED animals and reduced the sensation of ocular pain, as well as anxiety-like behaviors associated with severe DED. CONCLUSION: These data provide novel insights on the effectiveness of TRPV1 antagonist instillation in alleviating abnormal corneal neurosensory symptoms induced by severe DED, opening an avenue for the repositioning of this molecule as a potential analgesic treatment for patients suffering from chronic DED.

Deepening of lipidome annotation by associating cross-metathesis reaction with mass spectrometry: application to an in vitro model of corneal toxicity.

The in-depth knowledge of lipid biological functions needs a comprehensive structural annotation including a method to locate fatty acid unsaturations, which remains a thorny problem. For this purpose, we have associated Grubbs' cross-metathesis reaction and liquid chromatography hyphenated to tandem mass spectrometry to locate double bond positions in lipid species. The pretreatment of lipid-containing samples by Grubbs' catalyst and an appropriate alkene generates substituted lipids through cross-metathesis reaction under mild, chemoselective, and reproducible conditions. A systematic LC-MS/MS analysis of the reaction mixture allows locating unambiguously the double bonds in fatty acid side chains of phospholipids, glycerolipids, and sphingolipids. This method has been successfully applied at a nanomole scale to commercial standard mixtures consisting of 10 lipid subclasses as well as in lipid extracts of human corneal epithelial (HCE) cell line allowing to pinpoint double bond of more than 90 species. This method has also been useful to investigate the lipid homeostasis alteration in an in vitro model of corneal toxicity, i.e., HCE cells incubated with benzalkonium chloride. The association of cross-metathesis and tandem mass spectrometry appears suitable to locate double bond positions in lipids involved in relevant biological processes.

PreserFlo MicroShunt® exposure: a case series.

BACKGROUND: PreserFlo® MicroShunt (PM) (also known as InnFocus® MicroShunt) is a subconjunctival stent implanted ab externo via a minimally invasive surgical procedure. The current indication is progressive, mild to moderate, open angle glaucoma uncontrolled on topical medications. According to the literature, adverse events are rare, mild and transient. CASE PRESENTATION: Two cases of stand-alone PreserFlo MicroShunt® implantation in patients with uncontrolled open-angle glaucoma are reported. Exposure occurred 7 days and 3 months respectively after implantation. These cases shared common features including preexisting blepharitis and the lack of a Tenon's flap. In both cases, removal of the device was required after several attempts at repair. CONCLUSIONS: PreserFlo MicroShunt® exposure is a potentially vision-threatening complication because of the risk of endophthalmitis. Potential risk factors include the absence of a Tenon's flap and pre-existing ocular surface inflammation. Ocular surface inflammation should be detected and treated prior to PM implantation. If a deficiency in Tenon's capsule is noted intraoperatively, close monitoring should be performed because of the higher risk of PM exposure.

AOP and IATA applied to ocular surface toxicity.

Until now, the Draize test on rabbits has been the only test performed to anticipate ocular toxicity of pharmaceutical compounds, mainly irritation. The OECD is urging the scientific community to develop and validate alternative methods to reduce the need for animal testing. Since the models and tests used cannot reflect the entire biologic response, it is necessary to combine them into integrated approaches to testing and assessment (IATA) to obtain robust data. IATAs, along with adverse outcome pathways (AOP) that encompass molecular cascades and key events, require the best combinations of tests. This commentary manuscript describes these OECD tools and proposes original approaches for ocular surface AOP and an IATA for toxicity-induced dry eye (TIDE).

Comparison of Two Experimental Mouse Dry Eye Models through Inflammatory Gene Set Enrichment Analysis Based on a Multiplexed Transcriptomic Approach.

The goal of this study was to explore the specific signaling pathways related to inflammation in two experimental mouse dry eye (EDE) models. Female C57BL/6 mice housed for 10 days in a controlled desiccative environment were either treated with scopolamine (EDE-1; n = 18) or subjected to extraorbital lacrimal gland excision bilaterally (EDE-2; n = 10). Non-induced mice (n = 20) served as healthy controls. A corneal fluorescein staining (CFS) scoring was used at baseline through to day (D) 10 to evaluate epitheliopathy. At D10, corneas and conjunctivas were collected for multiplexed transcriptomic analysis with the NanoString® mouse inflammatory CodeSet. Both EDE-1 and EDE-2 mice presented a change in corneal integrity, with a significant increase in CFS scores at D10. More gene transcripts were identified in EDE-2 compared with EDE-1 (116 vs. 96, respectively), and only a few were common to both models, 13 for the cornea and 6 for the conjunctiva. The gene functional annotation analysis revealed that the same inflammatory pathways were involved in both models. Comparative profiling of gene expression in the two EDE models leads to the identification of various targets and signaling pathways, which can be extrapolated to and confirmed in human disease.

Influence of automated visual field testing on intraocular pressure.

BACKGROUND: To evaluate the influence of automated visual field (VF) testing on intraocular pressure (IOP) in patients with ocular hypertension (OHT) or glaucoma. METHODS: We conducted a prospective observational study in the glaucoma department at Quinze-Vingts National Ophthalmology Hospital in Paris. Ninety-five right eyes of 95 patients followed for glaucoma or OHT were included. IOP was measured three times using a Nidek NT-510 non-contact tonometer within a maximum of 5 min before and after VF testing. Sub analyses using logistic regression analysis were performed to evaluate the impact of gender, age, central corneal thickness (CCT), mean deviation (MD) of the VF, VF test duration and filtration surgery on IOP fluctuations. RESULTS: There was no significant change in IOP after VF testing, with IOP's 15.14 ± 4.00 mmHg before and 14.98 ± 3.33 mmHg after the VF (P = 0.4). The average change in IOP was 0.15 ± 1.82 mmHg. Using multivariate analysis, no effect of the VF test on IOP was found (global model fit R2 = 0.12), whether based on duration of the VF test (P = 0.18) or the MD (P = 0.7) after adjustment for age, gender, CCT and history of glaucoma surgery. Similarly, there was no significant difference within different types of glaucoma, including open-angle glaucoma (P = 0.36), chronic angle closure glaucoma (P = 0.85) and OHT (P = 0.42). The subgroup of patients with an IOP elevation ≥2 mmHg had a significantly higher VF test duration (P = 0.002). CONCLUSION: VF testing does not influence IOP as measured with a non-contact tonometer.

Cataract and glaucoma combined surgery: XEN® gel stent versus nonpenetrating deep sclerectomy, a pilot study.

BACKGROUND: To compare the efficacy of phacoemulsification (PKE) combined with nonpenetrating deep sclerectomy (NPDS) with mitomycin C (MMC) versus XEN® gel stent with MMC. METHODS: In this nonrandomized, retrospective, comparative, single-center pilot study, 105 consecutive eyes of 75 patients with uncontrolled primary open-angle glaucoma (POAG) and cataract who underwent PKE combined with either XEN implantation (n = 47) or NPDS (n = 58) between May 2013 and November 2018 were included. The primary outcome was complete success at 9 months, which was defined as intraocular pressure (IOP) ≤18, 15 or 12 mmHg without treatment; qualified success was IOP ≤18, 15 or 12 mmHg with antiglaucoma medications. Secondary outcome measures included the number of antiglaucoma medications, visual acuity (VA), and postoperative adverse events. RESULTS: Using the 18 mmHg threshold, complete or qualified success was achieved in 69.6 and 89.1% in the PKE + XEN group, and 63.8 and 89.7% in the PKE + NPDS group (p = .54 and p = .93), respectively, at 9 months. The mean IOP decreased from 20.8 ± 6.8 mmHg to 16.2 ± 2.8 mmHg in the PKE + XEN group (p < .001, 18.9% mean drop), and from 21.5 ± 8.9 mmHg to 14.9 ± 3.9 mmHg in the PKE + NPDS group (p < .001, 25.6% mean drop). Best-corrected VA significantly improved (p < .001) in both groups. The mean number of antiglaucoma medications was significantly reduced from 2.66 ± 1.1 to 0.49 ± 1.0 in the PKE + XEN group (p < .001) and from 2.93 ± 0.9 to 0.69 ± 1.2 in the PKE + NPDS group (p < .001). CONCLUSIONS: The XEN stent combined with PKE seemed to be as effective and safe as PKE + NPDS at 9 months in this pilot study.

Autologous Serum Eye Drops versus Artificial Tear Drops for Dry Eye Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

OBJECTIVE: To compare the efficacy of autologous serum (AS) eye drops and artificial tears (AT) in dry eye disease (DED). METHODS: Five databases (PubMed, Science Direct, the Cochrane Library, the Chinese National Knowledge Infrastructure, and the Wanfang Database) were searched for randomized controlled trials (RCTs). Efficacy was evaluated in terms of the Ocular Surface Disease Index (OSDI), Schirmer I test, tear break-up time (TBUT), and fluorescein and rose bengal staining of ocular surface. The estimated effects of AS or AT were expressed as a proportion with the 95% confidence interval and plotted on a forest plot. RESULTS: Seven RCTs with 267 subjects were included in the meta-analysis. For most of the studies, subjects' age was around 50 years old, and the mostly treatment duration was within 8 weeks. The follow-up results showed that the OSDI after AS treatment was lower than that after the AT treatment: the mean difference (MD) was -10.75 (95% CI, -18.12; -3.39) points. There was no difference on the Schirmer I test after treatment between the two groups: the MD was 1.68 (95% CI, -0.65; 4.00) mm. The TBUT of the AS group was longer than that of the AT group, with an MD of 4.53 (95% CI, 2.02; 7.05) s. There was no statistically significant difference on fluorescein staining score of the ocular surface between the AS group and the AT group, the MD was -2.53 (95% CI, -6.08; 1.03) points. The rose bengal staining score of the AS group was slightly lower than that of the AT group after treatment: the MD was -0.78 (95% CI, -1.34; -0.22) points. CONCLUSION: AS could be an effective treatment for DED, improving OSDI, TBUT, and rose bengal staining score. Further RCTs with large samples and long-term follow-up are still needed to determine the exact role of AS in the management of DED.

Prevalence of Unknown Ocular Hypertension, Glaucoma Suspects, and Glaucoma in Patients Seen in an Ophthalmology Center in France.

INTRODUCTION: The rate of unknown glaucoma is around 50% in industrialized countries. The purpose of our study was to estimate the prevalence of unknown cases of ocular hypertension, glaucoma suspects, and glaucoma in patients consulting for refractive disorders in France. METHODS: A retrospective study in the Point Vision ophthalmology center was led in Toulouse, France. All participants consulting for refractive disorders between June 2015 and June 2017 in the ophthalmology center were included. The cases were identified by the assessment of intraocular pressure, optic nerve head structure, and visual field. Ocular hypertension was defined as an intraocular pressure >21 mm Hg. Glaucoma was defined as the association of a glaucomatous papilla and two successive pathological visual fields. Glaucoma suspect was defined as the association of a glaucomatous papilla without visual field defect. The primary endpoint was the prevalence of unknown ocular hypertension, glaucoma suspects, and glaucoma in patients seen in an ophthalmology center. RESULTS: A total of 66,068 patients (mean age = 37 years) consulted for a refraction visual assessment during the study period. Among them, 234 had a visual field and a retinal nerve fiber layer assessment for ocular hypertension and/or suspicious papilla. The prevalence of unknown cases of ocular hypertension, glaucoma suspect, and glaucoma was 2.6, 0.8, and 0.5 per 1,000 consultants, respectively. Median age at diagnosis of ocular hypertension, glaucoma suspect, and glaucoma was 52, 53, and 65 years, respectively. CONCLUSION: The present study highlights the importance of glaucoma screening in people over 40 years old with the measurement of intraocular pressure and an optic nerve head assessment.

TRPM8: A Therapeutic Target for Neuroinflammatory Symptoms Induced by Severe Dry Eye Disease.

Dry eye disease (DED) is commonly associated with ocular surface inflammation and pain. In this study, we evaluated the effectiveness of repeated instillations of transient receptor potential melastatin 8 (TRPM8) ion channel antagonist M8-B on a mouse model of severe DED induced by the excision of extra-orbital lacrimal and Harderian glands. M8-B was topically administered twice a day from day 7 until day 21 after surgery. Cold and mechanical corneal sensitivities and spontaneous ocular pain were monitored at day 21. Ongoing and cold-evoked ciliary nerve activities were next evaluated by electrophysiological multi-unit extracellular recording. Corneal inflammation and expression of genes related to neuropathic pain and inflammation were assessed in the trigeminal ganglion. We found that DED mice developed a cold allodynia consistent with higher TRPM8 mRNA expression in the trigeminal ganglion (TG). Chronic M8-B instillations markedly reversed both the corneal mechanical allodynia and spontaneous ocular pain commonly associated with persistent DED. M8-B instillations also diminished the sustained spontaneous and cold-evoked ciliary nerve activities observed in DED mice as well as inflammation in the cornea and TG. Overall, our study provides new insight into the effectiveness of TRPM8 blockade for alleviating corneal pain syndrome associated with severe DED, opening a new avenue for ocular pain management.

Defining Dry Eye from a Clinical Perspective.

Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: "Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities." The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint.

Chronic dry eye induced corneal hypersensitivity, neuroinflammatory responses, and synaptic plasticity in the mouse trigeminal brainstem.

BACKGROUND: Dry eye disease (DED) is a multifactorial disease associated with ocular surface inflammation, pain, and nerve abnormalities. We studied the peripheral and central neuroinflammatory responses that occur during persistent DED using molecular, cellular, behavioral, and electrophysiological approaches. METHODS: A mouse model of DED was obtained by unilateral excision of the extraorbital lachrymal gland (ELG) and Harderian gland (HG) of adult female C57BL/6 mice. In vivo tests were conducted at 7, 14, and 21 days (d) after surgery. Tear production was measured by a phenol red test and corneal alterations and inflammation were assessed by fluorescein staining and in vivo confocal microscopy. Corneal nerve morphology was evaluated by nerve staining. Mechanical corneal sensitivity was monitored using von Frey filaments. Multi-unit extracellular recording of ciliary nerve fiber activity was used to monitor spontaneous corneal nerve activity. RT-qPCR and immunostaining were used to determine RNA and protein levels at d21. RESULTS: We observed a marked reduction of tear production and the development of corneal inflammation at d7, d14, and d21 post-surgery in DED animals. Chronic DE induced a reduction of intraepithelial corneal nerve terminals. Behavioral and electrophysiological studies showed that the DED animals developed time-dependent mechanical corneal hypersensitivity accompanied by increased spontaneous ciliary nerve fiber electrical activity. Consistent with these findings, DED mice exhibited central presynaptic plasticity, demonstrated by a higher Piccolo immunoreactivity in the ipsilateral trigeminal brainstem sensory complex (TBSC). At d21 post-surgery, mRNA levels of pro-inflammatory (IL-6 and IL-1ß), astrocyte (GFAP), and oxidative (iNOS2 and NOX4) markers increased significantly in the ipsilateral trigeminal ganglion (TG). This correlated with an increase in Iba1, GFAP, and ATF3 immunostaining in the ipsilateral TG of DED animals. Furthermore, pro-inflammatory cytokines (IL-6, TNFα, IL-1ß, and CCL2), iNOS2, neuronal (ATF3 and FOS), and microglial (CD68 and Itgam) markers were also upregulated in the TBSC of DED animals at d21, along with increased immunoreactivity against GFAP and Iba1. CONCLUSIONS: Overall, these data highlight peripheral sensitization and neuroinflammatory responses that participate in the development and maintenance of dry eye-related pain. This model may be useful to identify new analgesic molecules to alleviate ocular pain.

Long term effect of phacoemulsification on intraocular pressure in patients with medically controlled primary open-angle glaucoma.

BACKGROUND: The effect of cataract surgery on IOP in patients with primary open-angle glaucoma (POAG) is a subject of debate. We investigated the effect of cataract surgery by phacoemulsification on intraocular pressure (IOP) in patients with medically POAG . METHODS: Seventy eyes of 40 POAG patients undergoing cataract surgery by phacoemulsification were retrospectively evaluated. All patients had their POAG medically controlled without prior glaucoma surgery. Baseline demographics and clinical characteristics were recorded. IOP and the number of glaucoma medications were evaluated before and for 1 year after cataract surgery. We analyzed IOP variations from baseline with a Student t-test for a paired sample. We used a Pearson correlation coefficient and linear regression to study the relation between IOP change from baseline and preoperative characteristics. RESULTS: One year after phacoemulsification, IOP decreased by a mean 1.15 ± 3 mmHg (6.8 ± 18.1%) (P = 0.01) and the number of glaucoma medications remained unchanged with a difference of - 0.1 ± 0.43 (P = 0.09). Higher preoperative IOP was associated with a greater IOP decrease after 1 year of follow-up (P < 0.001). One and 7 days after cataract surgery, 12.9 and 4.2% of the eyes had IOP spikes > 30 mmHg, respectively. One year after cataract surgery, 75.7% of the POAG eyes maintained the same number of glaucoma medications while 17.1% had a decrease and 7.2% of the eyes required adding glaucoma medications. CONCLUSION: Cataract surgery by phacoemulsification in eyes with medically controlled POAG resulted at 1 year in a very small IOP decrease without a change in the number of glaucoma medications. A drop in IOP should not be expected after performing phacoemulsification alone in POAG patients.

Changes in choroidal thickness and optic nerve head morphology after filtering surgery: nonpenetrating deep sclerectomy versus trabeculectomy.

BACKGROUND: The purpose of this study was to evaluate the changes in choroidal thickness and lamina cribrosa position after nonpenetrating deep sclerectomy (NPDS) and trabeculectomy. METHODS: Twenty-three eyes with glaucoma that required filtering surgery were included (12 NDPS and 11 trabeculectomies) in this prospective observational study. OCT-enhanced depth imaging (OCT-EDI) was used to measure choroidal thickness, prelaminar tissue thickness and lamina cribrosa position before and 7 days and 1 month after surgery. All results are shown as median (interquartile range values). RESULTS: Intraocular pressure (IOP) was significantly lower 1 week after surgery than at baseline (7 (6/10) mmHg vs. 21 (18/26) mmHg; p < 0.001) with a mean 64% decrease. IOP remained significantly lower at 1 month with a 55% mean decrease as compared to baseline (10 (8/12) mmHg; p < 0.001). One week after surgery, the subfoveolar choroidal thickness (SFCT) significantly increased (372 (306/523) µm vs. 317 (227/413) µm; p = 0.04) and the prelaminar tissue (PLT) was significantly thicker (269 (162/360) µm vs. 138 (87/268) µm; p = 0.02) as compared to preoperative measurements. These changes were not statistically significant at one month. There were no differences concerning these parameters between the NPDS and trabeculectomy groups. During the first week, the SFCT increase was correlated with IOP reduction (r = - 0.41; p = 0.04). CONCLUSIONS: OCT-EDI allowed the visualization of structural changes at the level of the optic nerve and choroidal vascularization during acute IOP changes. No difference was observed between NPDS and trabeculectomy concerning these structural modifications.