Dry Eye Disease – Current Insights and Future Perspectives

European Ophthalmic Review, 2017;11(Suppl 1):3–9


The key factors driving dry eye disease (DED) are tear film instability, tear hyperosmolarity, apoptosis and inflammation, which can lead to corneal damage, keratitis, cytokine release and nerve stimulation, forming a self-sustaining ‘vicious circle’. These factors degrade the quality of vision, which worsens with disease severity. The pathophysiology of DED affects the entire ocular surface system involving the innate and adaptive immune systems, and the mechanisms are becoming recognised as more wide-ranging than was previously understood. Many patients show a discrepancy between signs such as corneal fluorescence staining (CFS) and DED symptoms at diagnosis and during treatment, which makes assessment challenging. In response to this, new grading schemes such as those of the ODISSEY European Consensus Group have been developed to aid diagnosis of severe DED. A key treatment for DED is the immunomodulatory agent, topical ciclosporin A (CsA) eye drops (0.1% CsA, Ikervis, Santen). Clinical studies such as the phase III SANSIKA trial (n=246) showed significant reductions in ocular surface inflammation after 6 months of patients receiving 0.1% CsA compared with vehicle (p=0.021). A post hoc analysis of this study in patients with CFS improvement of ≥3 grades revealed a significant treatment effect in which there were more responders to topical CsA treatment than to vehicle (p=0.016). In this trial 0.1% CsA was well tolerated and required only a single daily instillation in contrast with others requiring multiple daily doses. Wider use of topical CsA and better understanding of the inflammatory processes in DED may lead to improved treatments in this debilitating disease.
Keywords: Dry eye disease, corneal damage, keratitis, variable signs, grading scheme, ciclosporin, case examples
Disclosure: Maurizio Rolando is a consultant or has been sponsored by, or received research grants, from Alcon, Allergan, Bausch & Lomb, Dompé, Farmigea, OFF, Pfizer, Santen, Thea, Novartis and TRB Chemedica. Christophe Baudouin has received consultant fees and research grants from Alcon, Allergan, Dompé, Horus Pharma, Santen and Thea and has received academic financial support and grants from INSERM (Institut National de la Santé et la Recherche Médicale), UMRS968, and University Paris 6 and Labex Lifesenses (reference ANR-10-LABX-65). José Benitez-Del-Castillo has been sponsored by or received research grants from Santen, Bausch & Lomb, AbbVie, Angelini, Horus, Alcon, Allergan, Thea, Esteve and Dompé. This article has not been submitted to external peer reviewers but was reviewed by the advisory board for accuracy before publication.
Acknowledgments: Medical writing assistance was provided by James Gilbart at Touch Medical Media and funded by Santen EMEA.
Received: May 22, 2017 Published Online: August 10, 2017
Correspondence: Maurizio Rolando, Department of Neurosciences, Ophthalmology and Genetics, University of Genoa, 16132 Genoa, Italy. E: maurizio.rolando@gmail.com
Support: The ECLSO satellite symposium was organised and funded by Santen EMEA. The publication of this article was supported by Santen EMEA. The views and opinions expressed are those of the authors and not necessarily those of Santen EMEA.
Open Access: This article is published under the Creative Commons Attribution Noncommercial License, which permits any non-commercial use, distribution, adaptation and reproduction provided the original author(s) and source are given appropriate credit.

Understanding the severity of keratitis and its impact in severe dry eye disease
The target mechanisms that drive the pathophysiology of dry eye disease (DED) are principally tear film instability, tear hyperosmolarity, apoptosis and inflammation. These factors, respectively, lead to cell damage, nerve stimulation, cytokine release, matrix metalo-proteinase activation and goblet cell loss and form a ‘vicious circle’ that can repeat multiple times.1,2 DED is rarely just a tear problem; it is usually related to disruption of the ocular surface and altered activity in the corneal epithelium. In DED, there is usually increased production of pro-inflammatory cytokines, release of prostaglandins and leukotrienes that activate leukocytes and enzymes. In addition, there is expression of adhesion molecules responsible for leukocyte tissue infiltration and expression of major histocompatibility complex (MHC) class II peptides that are responsible for antigen presentation and T lymphocyte activation.3 In addition, natural or artificial tears will not form the normal film over the epithelium, resulting in dry eyes, vulnerability to infection and corneal damage.4 It is, therefore, essential to address corneal problems in patients with DED. Inflammation of the cornea (keratitis) is itself a source of further inflammation and thus the process is self-sustaining.

The air–tear interface is the most important refractive interface in the eye and the cornea is responsible for two-thirds of optical power. DED and keratitis, however, can degrade the quality of vision, increase secondary infection risk and reduce quality of life in DED patients.5,6 This was emphasised in a study of 52 patients with DED, in which reading speeds were significantly reduced compared with normal control subjects, and this effect worsened with severity of disease.7 This study also showed that central corneal punctate keratitis significantly affected reading speed compared with peripheral staining or normal corneas.

Several studies that included a combined total of approximately 90 patients with epithelial disease showed that the increasing ocular surface damage is associated with decreasing level of contrast sensitivity and this has proven to be a useful measure of DED severity (see Figure 1).8–11 In another study, 20 patients with DED were found to have visual impairment that diminished their capability to drive compared with 20 age- and sex-matched controls (p0.01).12

Corneal epithelium changes in dry eye disease
The corneal epithelium is highly impermeable, largely due to the tight junctions between cells at the surface. This creates a potential difference across the epithelium. The surface is charged negatively compared with the interior, which has a more positive charge.13 This is advantageous because most environmental pathogens are negatively charged at the surface and so are not attracted to the corneal surface. If the tight junction is interrupted, as it is in DED, this repulsion is lost, allowing ingress of bacteria. Analysis of corneal surfaces in patients with DED reveals epithelial punctate keratopathy, sub-epithelial nerve plexus damage and stromal keratocyte activation. Such corneas also show sub-epithelial invasion with mature dendritic cells.14,15 This indicates a profound change in the immune condition of the cornea. In addition, in inflamed corneas in DED there is a change in the appearance of corneal nerves which show increased tortuosity, reduced length, decreased thickness and increased beading.

Markers and grading scales to address challenges in severe dry eye disease diagnosis
For assessment of DED, epithelial punctate keratopathy is an important feature for grading the level of chronic corneal damage and the severity of the disease.16,17 In addition, the epithelial cells of the cornea express inflammatory markers including matrix metallopeptidase 9 (MMP9), interleukin-1 (IL-1), IL-6, IL-8, IL-16, IL-33, human leukocyte antigen-antigen D related (HLA-DR), CD69, CD154 and transforming growth factor-alpha (TGF-α) and these factors all have potential as laboratory indicators of disease.18–24 In addition, lissamine green and fluorescein stains (used with a Wratten 12 filter) enable the visualisation of keratitis. The diagnosis and severity of disease using these stains is assisted using one or more grading scales including the Oxford (most commonly used), National Eye Institute (NEI), SICCA Ocular Staining Score, Efron etc.25–28 These use different criteria to produce a severity score within a defined scale. The Oxford scale gives some indication of the position of staining on the ocular surface.25 The NEI-Industry Workshop in 1995 produced a more precise scale to more accurately record the position and extent of staining.27 There is, however, no universal consensus among investigators and clinicians on the best single grading scale to use in DED.

In many patients there is discrepancy between signs and symptoms in DED making diagnosis and the assessment of treatment efficacy difficult. To address this issue the ODISSEY Consensus Group proposed a new approach for severe DED diagnosis.16 This group of experts in the field of DED from across Europe devised an algorithm that could be used when there is discordance between primary assessment criteria (symptom-based assessment and corneal fluorescence staining [CFS]). This algorithm consists of three scenarios that would determine additional criteria recommended to further evaluate DED severity. These are: scenario A (Ocular Surface Disease Index [OSDI] Figure 2 and the additionally required criteria are listed in Table 1. Use of this scheme may help in the diagnosis of DED.

Inflammation – the new target to treat dry eye disease
DED is not a syndrome but a disease of the tear film that involves inflammation, which is a ubiquitous mechanism in ocular surface diseases (OSDs). The International Dry Eye Workshop (DEWS I) provided a consensus definition of DED in 2007.29 DEWS II met in September 2016 and provided an updated definition: ‘Dry eye is a multifactorial disease of the ocular surface characterised by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles.’

The variable signs of dry eye disease
In DED, signs of inflammation can be difficult to identify even though it plays a key role; there is often a lack of redness, swelling or pain (which often feels ‘uncomfortable’ rather than ‘painful’) that are the classical signs of inflammation. There are two main classes of dry eye, which are aqueous deficient (ADDE) and evaporative (EDE) types. In ADDE, there is a reduction in tear flow and volume, whereas in EDE tear production is normal but there is increased evaporation.30 In a recent retrospective study of 224 patients with DED conducted in the US, 79 (35%) were found to have EDE (caused by meibomian gland dysfunction [MGD]), 23 (10%) had ADDE and the remaining 55% had a mixed or unknown type.31 MGD is the leading cause of EDE.32 Among ADDEs, Sjogren’s syndrome (SS) is a frequent cause in addition to lacrimal deficiency, lacrimal duct obstruction, reflex block and systemic drugs.

The pathophysiology of dry eye disease
In the proposed ‘vicious circle’ mechanism of DED, tear film instability or deficiency leads to hyperosmolarity, cell damage, apoptosis, nerve

stimulation, inflammation, cytokine release and goblet cell loss which in turn, leads to greater tear film instability.1 These factors are affected by a range of disease, lifestyle, drug and environmental factors. When such influences are chronic, or multiple factors are present, the patient can enter a self-stimulated loop that maintains or worsens the disease.33 MGD is affected by these same factors but is also affected by an additional vicious circle involving meibomian gland blockage/inflammation, leading to bacterial flora changes, esterase and lipase changes and lipid alterations, which result in further meibomian gland blockage.1,34

The mechanisms of DED are increasingly recognised as more wideranging than was previously understood. A new concept is that DED is a mucosal autoimmune disease that is not restricted to the ocular surface but involves the lacrimal glands, corneal and conjunctival epithelia and meibomian glands that form the ocular surface system. In addition, the disease involves the innate and adaptive immune systems. Stress to the ocular surface results in a pro-inflammatory cytokine response and upregulation or exposure of autoantigens (e.g. M3R and KLK13).35,36 This results in self-antigen recognition through B-cell receptor antigen presentation, leading to autoantibody presentation with consequent tissue damage. In addition, in DED, mechanisms that maintain homeostasis of the ocular surface, which are mediated by nerve connections and systemic hormones, are disrupted.14

Immune aspects of dry eye disease
The importance of the immune component in the DED mechanism has been demonstrated in various in vitro, in vivo and clinical studies and these increase understanding of the mode of action of a newer treatment approach. In one study, human conjunctival cells were exposed

to hyperosmolar conditions which induced an increase in secretion of the chemokine C-C motif ligand 2 (CCL2).37 This increase, however, was substantially reduced with the addition of either ciclosporin A (CsA) or dexamethasone. Further evidence of the mechanism of CsA action in DED was provided by a study of clinical conjunctival biopsies.38 Biopsies from patients with DED treated with topical CsA showed decreases in cells positive for cluster of differentiation 3 (CD3), CD4, CD8 antigens compared with increases in control-treated patients. In addition, CsA treatment also significantly reduced lymphocyte activation markers CD11a and HLA-DR compared with controls (p38 Biopsies from patients with the autoimmune disease, SS showed significant decreases in CD11a (p

In a large study that included 311 patients, flow cytometry on cells from corneal imprints showed that HLA-DR was significantly increased in patients with SS (p39 Levels of HLA-DR were found to be positively correlated with corneal fluorescence staining (r=0.30, p41

Other studies have provided evidence that DED is an inflammatory disease. In one example, impression cytology methods and flow cytometry were used to collect and analyse cells from the corneas of 243 patients with DED with or without SS and 50 from control individuals.20 Cells from DED patients with or without SS were shown to significantly overexpress inflammatory and apoptosis-related markers (e.g. HLADR, CD40, transmembrane protein [Fas] and mitochondrial membrane antigen [APO2.7]) compared with cells from normal eyes. These data supported the use of immunomodulatory and or anti-inflammatory drug in DED treatment.

Neuropathic pain – a frequent lasting effect of dry eye disease
Neuropathic pain is a significant issue in DED. Many patients continue to have inflammation and experience severe pain despite showing corneal improvements. Studies using confocal microscopic analysis of ocular tissues have shown abnormal nerve appearance in DED that are associated with lower sensitivity to mechanical, thermal and chemical stimuli.42 It is speculated that in chronic cases these alterations may ‘imprint’ on the trigeminal pathway, creating long-term pain. This raises a series of unanswered questions such as why some patients with DED evolve toward hyposensitivity of the cornea mostly when it is extensively damaged and why sensitivity is retained in others. Other questions include: why continuous corneal nerve stimulation would induce neurogenic inflammation? and whether second order neuron stimulation could play a role even when the cornea recovers or improves?

Recent work in mice has shown that induction of inflammation in the eye using benzalkonium chloride instillation reduced tear production and increased inflammatory cell infiltration.43 This inflammation induced activation of neurons and microglial p38 mitogen-activated protein kinase (MAPK) pathway in the sensory trigeminal complex. This suggested that inflammation could have a priming role in the sensitisation of ocularrelated brainstem nerves, which is a key factor in pain development.

Treatments that target inflammation in dry eye disease
A limited number of treatments that address inflammation in DED currently exist although few are approved for this indication. Of interest are lifitegrast (an integrin lymphocyte function associated antigen binding inhibitor – approved in the US only) and CsA (an inhibitor of T-cell function and IL-2 release). Topical CsA (CsA 0.05%) treatment was approved to increase tear production in patients whose tear production is presumed to be suppressed due to ocular inflammation associated with DED by the US FDA in 2003 and more recently for severe keratitis in DED in Europe in 2015 (Ikervis®, 0.1% CsA, Santen, Evry, France) following successful phase III clinical trials (Table 2).1,41 In addition to these, there is a large series of targets that could be exploited to better address inflammation in DED (Table 3) and drugs that act on these targets may improve future management of DED.

Ciclosporin in the treatment of severe keratitis in dry eye disease – today and tomorrow
Currently, there is substantial disagreement on the definition and diagnosis of DED. This is due to DED being viewed either as a disease or as a range of different symptoms or ocular surface condition or as a condition that is associated with other conditions.44 This situation may be improved with the forthcoming publication of the revised DEWS definitions and classifications. These guidelines indicate escalating treatments according to DED severity level (Table 4). Differentiating between sequential severity levels, however, can be challenging especially when there is a discrepancy between signs and symptoms as discussed previously.

Ciclosporin A – a key treatment in dry eye disease
A key treatment for severe (level 4) DED is topical CsA. This is a cyclic undecapeptide of fungal origin. It is widely used as immunomodulation to inhibit rejection of organs after transplant surgery and to control some autoimmune disorders. CsA inhibits activation of T lymphocytes and apoptosis by binding to cyclophilin A and D. Topical CsA is a valuable treatment in various ocular conditions including DED, types of keratoconjunctivitis, and types of keratitis.45,46 CsA has notable safety advantages over corticosteroids but has a low solubility in water and is formulated as a topical emulsion.

In the multicentre, randomised controlled, phase III SANSIKA trial, 246 patients with severe DED were randomised to receive daily 0.1% CsA

eye drops lipid emulsion (Ikervis, 0.1% CsA) or vehicle (the same lipid emulsion found in Ikervis but without CsA) for 6 months followed by a 6-month open-label safety follow-up period.41 The primary endpoint was the proportion of patients who achieved ≥2 grades of improvement in CFS and ≥30% improvement in OSDI by month 6. The initial analysis showed a numerical advantage for CsA that was not statistically significant (28.6% for 0.1% CsA versus 23.1% for vehicle treatment [p=0.326]). In addition, the mean OSDI changes from baseline in these groups were similar (-13.6% for CsA and -14.1% for vehicle at month 6 [p=0.858]). However, there was a significant difference in reduction in ocular surface inflammation (assessed by HLA-DR expression) at month 6 (p=0.021) in favour of CsA. The most frequent adverse event was instillation site pain (29.2% for CsA versus 8.9% for vehicle), which was mostly mild.

A post hoc analysis of the primary efficacy endpoint (CFS-OSDI responder rates) was conducted to explore a potential treatment effect on patients who had a marked improvement in CFS over 6 months.41 In this analysis, the threshold for improvement of CFS was increased from ≥2 grades to ≥3 grades. Using this more stringent criterion, there were 29 (18.8%) responders receiving CsA versus seven (7.8%) receiving vehicle (p=0.016) (Figure 3), which showed a significant treatment effect.41

The SANSIKA trial, therefore, showed that a topical formulation of 0.1% CsA was well tolerated and effective in improving corneal surface damage and ocular surface inflammation among responders. These benefits were achieved with a single daily instillation that contrast with other DED treatments that require multiple instillations for optimal efficacy.

The benefits of 0.1% CsA in patients with severe DED who have not responded to previous treatments are illustrated in the two typical case

examples below. In both cases symptoms were resolved within a few months after commencing 0.1% CsA topical treatment.

DED continues to be a serious medical burden, causing visual disturbance and discomfort, especially in the elderly. It affects up to 100 million individuals globally, but prevalence varies depending on the populations studied.47–49 The prevalence of the condition is likely to increase as worldwide populations age. Reliable diagnostic methods, clear guidelines for best practice and effective, tolerable treatments are therefore critical in the present and future management of DED. It is increasingly understood that DED is not simply a disease confined to the ocular surface but affects structures of the entire ocular surface system and the trigeminal pathway. As such, DED involves both inflammatory and immune processes operating in a ‘vicious circle’ which serves to maintain the disease after it is initiated by a variety of different factors. Diagnostic and treatment approaches to the disease should take account of these factors to control it effectively.

The lack of consensus on a definition and diagnostic process in DED remains a problem that hampers good management. In addition, clinical experience, as discussed in the sections above, highlights the serious discrepancy between signs and symptoms in DED. Some patients may not present with all the expected symptoms of DED and consequently may not be correctly diagnosed leading to appropriate treatment not being received or being much delayed. It is important that patients with suspected or possible DED are investigated thoroughly using appropriate staining, and graded correctly using a scheme such as that of the ODISSEY Consensus Group, which has attempted to address diagnostic difficulties.16 In DED there is currently a lack of good biomarkers in clinical use. HLA-DR, MMP-9, cytokine profiles, lactoferin/lysozyme and tear osmolarity have potential in the clinical diagnosis of DED51 as shown by clinical studies and case examples. Other potential biomarkers for this disease such as antibodies are now emerging using proteomic approaches.50 Another evolving diagnostic approach in ocular surface disease is confocal microscopy. This technique is largely confined to in vivo research studies but work is in progress to move it from the bench to the bedside.51

0.1% CsA is currently the only approved topical medication for severe keratitis for patients with DED in the EU. Findings from clinical trials support its use in this indication. The efficacy was particularly apparent when a higher threshold of improvement of 3 CFS grades was used in a post-hoc analysis. The treatment was well tolerated with pain at instillation the only frequently reported adverse event. In many patients with DED, however, neuropathic pain can persist for a long time after other symptoms have resolved. This pain may be primed by inflammation but the relationship between nerves and DED needs much further investigation and managing pain continues to be a challenge in DED.

The two case reports show that the treatment is also effective in real-world clinical use. Both patients had severe DED and keratitis and had not responded to previous treatments but improved after 0.1% CsA treatment. The cases also emphasised that corneal disease is reversible but takes time. It is essential to inform patients not to expect rapid resolution of their symptoms.

In future, better consensus approaches, greater adherence to current guidelines, improved, more rapid diagnosis, correct grading and willingness to use appropriate treatments are likely to reduce the burden and enhance outcomes in DED. The use of stem cells also has potential as a treatment approach in DED. Increased knowledge of inflammatory and immune processes has identified a range of potential drug targets. The exploitation of these approaches may eventually lead to a broader range of effective treatments for this increasingly common and debilitating ocular disease.

1. Baudouin C, Amrane M, Leonardi A, et al., Changing paradigms of treating severe keratitis in dry eye disease, European Ophthalmic Review, 2015;9:121–7.
2. Baudouin C, Aragona P, Messmer EM, et al., Role of hyperosmolarity in the pathogenesis and management of dry eye disease: proceedings of the OCEAN group meeting, Ocul Surf, 2013;11:246–58.
3. Aragona P, Rania L, Ruzzolo D, In: Ocular Surface Disease, Benitez-del-Castillo JM, Michael A Lemp (eds), London: JP Medical Ltd, 2013.
4. Tauber S, Scar Wars: Managing Dry Eye Associated With LASIK, Ophthalmology Management, 2007. Available at: www.ophthalmologymanagement.com/articleviewer. aspx?articleID=101023 (accessed 12 June 2017).
5. Narayanan S, Redfern RL, Miller WL, et al., Dry eye disease and microbial keratitis: is there a connection?, Ocul Surf, 2013;11:75–92.
6. Uchino M, Schaumberg DA, Dry eye disease: Impact on quality of life and vision, Curr Ophthalmol Rep, 2013;1:51–7.
7. Ridder WH, 3rd, Zhang Y, Huang JF, Evaluation of reading speed and contrast sensitivity in dry eye disease, Optom Vis Sci, 2013;90:37–44.
8. Kaido M, Ishida R, Dogru M, et al., The relation of functional visual acuity measurement methodology to tear functions and ocular surface status, Jpn J Ophthalmol, 2011;55:451–9.
9. Kaido M, Matsumoto Y, Shigeno Y, et al., Corneal fluorescein staining correlates with visual function in dry eye patients, Invest Ophthalmol Vis Sci, 2011;52:9516–22.
10. Koh S, Maeda N, Hori Y, et al., Effects of suppression of blinking on quality of vision in borderline cases of evaporative dry eye, Cornea, 2008;27:275–8.
11. Rolando M, Iester M, Macri A, et al., Low spatial-contrast sensitivity in dry eyes, Cornea, 1998;17:376–9.
12. Deschamps N, Ricaud X, Rabut G, et al., The impact of dry eye disease on visual performance while driving, Am J Ophthalmol, 2013;156:184–9 e3.
13. Abelson MB, Mandell KD, Howe AJ, When tight junctions aren’t tight enough A look at the eye’s remarkable defenses and the ways allergens can defeat them, Review of Ophthalmology, 2009. Available at: www.reviewofophthalmology.com/article/whentight- junctions-arent-tight-enough (accessed 12 June 2017).
14. Barabino S, Chen Y, Chauhan S, et al., Ocular surface immunity: homeostatic mechanisms and their disruption in dry eye disease, Prog Retin Eye Res, 2012;31:271–85.
15. Hamrah P, Liu Y, Zhang Q, et al., Alterations in corneal stromal dendritic cell phenotype and distribution in inflammation, Arch Ophthalmol, 2003;121:1132–40.
16. Baudouin C, Aragona P, Van Setten G, et al., Diagnosing the severity of dry eye: a clear and practical algorithm, Br J Ophthalmol, 2014;98:1168–76.
17. Behrens A, Doyle JJ, Stern L, et al., Dysfunctional tear syndrome: a Delphi approach to treatment recommendations, Cornea, 2006;25:900–7.
18. Aragona P, Aguennouz M, Rania L, et al., Matrix metalloproteinase 9 and transglutaminase 2 expression at the ocular surface in patients with different forms of dry eye disease, Ophthalmology, 2015;122:62–71.
19. Baudouin C, Brignole F, Pisella PJ, et al., Immunophenotyping of human dendriform cells from the conjunctival epithelium, Curr Eye Res, 1997;16:475–81.
20. Brignole F, Pisella PJ, Goldschild M, et al., Flow cytometric analysis of inflammatory markers in conjunctival epithelial cells of patients with dry eyes, Invest Ophthalmol Vis Sci, 2000;41:1356–63.
21. Brignole-Baudouin F, Baudouin C, Aragona P, et al., A multicentre, double-masked, randomized, controlled trial assessing the effect of oral supplementation of omega-3 and omega-6 fatty acids on a conjunctival inflammatory marker in dry eye patients, Acta Ophthalmol, 2011;89:e591–7.
22. El Annan J, Chauhan SK, Ecoiffier T, et al., Characterization of effector T cells in dry eye disease, Invest Ophthalmol Vis Sci, 2009;50:3802–7.
23. Na KS, Mok JW, Kim JY, et al., Correlations between tear cytokines, chemokines, and soluble receptors and clinical severity of dry eye disease, Invest Ophthalmol Vis Sci, 2012;53:5443–50.
24. Rolando M, Barabino S, Mingari C, et al., Distribution of conjunctival HLA-DR expression and the pathogenesis of damage in early dry eyes, Cornea, 2005;24:951–4.
25. Bron AJ, Evans VE, Smith JA, Grading of corneal and conjunctival staining in the context of other dry eye tests, Cornea, 2003;22:640–50.
26. Lasswell L, Huth S, Tran D, Deciphering Corneal Staining Scales, Contact Lens Spectrum. A look at the impact of grading scales and study designs on corneal staining results in clinical studies. 2007. Available at: www.clspectrum.com/issues/2007/ april-2007/deciphering-corneal-staining-scales (accessed 1 August 2017).
27. Lemp MA, Report of the National Eye Institute/Industry workshop on Clinical Trials in Dry Eyes, CLAO J, 1995;21:221–32.
28. van Bijsterveld OP, Diagnostic tests in the Sicca syndrome, Arch Ophthalmol, 1969;82:10–4.
29. DEWS, The definition and classification of dry eye disease: report of the Definition and Classification Subcommittee of the International Dry Eye WorkShop (2007), Ocul Surf, 2007;5:75–92.
30. Jeon HS, Youn SW, Jeon HE, et al., Assessment of Transepidermal Water Loss From the Ocular Area in Dry Eye Disease, Invest Ophthalmol Vis Sci, 2016;57:4831–6.
31. Lemp MA, Crews LA, Bron AJ, et al., Distribution of aqueousdeficient and evaporative dry eye in a clinic-based patient cohort: a retrospective study, Cornea, 2012;31:472–8.
32. Nichols KK, Foulks GN, Bron AJ, et al., The international workshop on meibomian gland dysfunction: executive summary, Invest Ophthalmol Vis Sci, 2011;52:1922–9.
33. Baudouin C, [A new approach for better comprehension of diseases of the ocular surface], J Fr Ophtalmol, 2007;30:239–46.
34. Baudouin C, Messmer EM, Aragona P, et al., Revisiting the vicious circle of dry eye disease: a focus on the pathophysiology of meibomian gland dysfunction, Br J Ophthalmol, 2016;100:300–6.
35. Pflugfelder SC, De Paiva CS, Moore QL, et al., Aqueous Tear Deficiency Increases Conjunctival Interferon-gamma (IFNgamma) Expression and Goblet Cell Loss, Invest Ophthalmol Vis Sci, 2015;56:7545–50.
36. Stern ME, Schaumburg CS, Pflugfelder SC, Dry eye as a mucosal autoimmune disease, Int Rev Immunol, 2013;32:19–41.
37. Warcoin E, Baudouin C, Baudouin F, Cyclosporine inhibits hyperosmolarity-induced CCL2 secretion by conjunctival cells in an in vitro model of dry eye (ARVO abstract), Invest Ophthalmol Vis Sci, 2015;56:332.
38. Kunert KS, Tisdale AS, Stern ME, et al., Analysis of topical cyclosporine treatment of patients with dry eye syndrome: effect on conjunctival lymphocytes, Arch Ophthalmol, 2000;118:1489–96.
39. Baudouin C, Liang H, Riancho L, et al., Correlation between the Inflammatory Marker HLA DR and Signs and Symptoms in moderate to severe Dry Eye Disease (ARVO abstract), Invest Ophthalmol Vis Sci, 2015 56:298.
40. Versura P, Profazio V, Schiavi C, et al., Hyperosmolar stress upregulates HLA-DR expression in human conjunctival epithelium in dry eye patients and in vitro models, Invest Ophthalmol Vis Sci, 2011;52:5488–96.
41. Leonardi A, Van Setten G, Amrane M, et al., Efficacy and safety of 0.1% cyclosporine A cationic emulsion in the treatment of severe dry eye disease: a multicenter randomized trial, Eur J Ophthalmol, 2016;26:287–96.
42. Benitez-Del-Castillo JM, Acosta MC, Wassfi MA, et al., Relation between corneal innervation with confocal microscopy and corneal sensitivity with noncontact esthesiometry in patients with dry eye, Invest Ophthalmol Vis Sci, 2007;48:173–81.
43. Launay PS, Reboussin E, Liang H, et al., Ocular inflammation induces trigeminal pain, peripheral and central neuroinflammatory mechanisms, Neurobiol Dis, 2016;88:16–28.
44. Chao W, Belmonte C, Benitez Del Castillo JM, et al., Report of the Inaugural Meeting of the TFOS i(2) = initiating innovation series: Targeting the unmet need for dry eye treatment, Ocul Surf, 2016;14:264–316.
45. Levy O, Labbe A, Borderie V, et al., [Topical cyclosporine in ophthalmology: Pharmacology and clinical indications], J Fr Ophtalmol, 2016;39:292–307.
46. Tatlipinar S, Akpek EK, Topical ciclosporin in the treatment of ocular surface disorders, Br J Ophthalmol, 2005;89:1363–7.
47. DEWS, The epidemiology of dry eye disease: report of the Epidemiology Subcommittee of the International Dry Eye WorkShop (2007), Ocul Surf, 2007;5:93–107.
48. Lemp MA, Sullivan BD, Crews LA, Biomarkers In Dry Eye Disease, European Ophthalmic Review, 2012;6:157–63.
49. Pflugfelder SC, Prevalence, burden, and pharmacoeconomics of dry eye disease, Am J Manag Care, 2008;14:S102–6.
50. Al Kindi MA, Colella AD, Chataway TK, et al., Secreted autoantibody repertoires in Sjogren’s syndrome and systemic lupus erythematosus: A proteomic approach, Autoimmun Rev, 2016;15:405–10.
51. Villani E, Baudouin C, Efron N, et al., In vivo confocal microscopy of the ocular surface: from bench to bedside, Curr Eye Res, 2014;39:213–31.
52. Yoon KC, Jeong IY, Park YG, et al., Interleukin-6 and tumor necrosis factor-alpha levels in tears of patients with dry eye syndrome, Cornea, 2007;26:431–7.
53. Nguyen CQ, Yin H, Lee BH, et al., Pathogenic effect of interleukin-17A in induction of Sjogren’s syndrome-like disease using adenovirus-mediated gene transfer, Arthritis Res Ther, 2010;12:R220.
54. Goyal S, Chauhan SK, Zhang Q, et al., Amelioration of murine dry eye disease by topical antagonist to chemokine receptor 2, Arch Ophthalmol, 2009;127:882–7.
55. El Annan J, Goyal S, Zhang Q, et al., Regulation of T-cell chemotaxis by programmed death-ligand 1 (PD-L1) in dry eye-associated corneal inflammation, Invest Ophthalmol Vis Sci, 2010;51:3418–23.
56. Seo MJ, Kim JM, Lee MJ, et al., The therapeutic effect of DA- 6034 on ocular inflammation via suppression of MMP-9 and inflammatory cytokines and activation of the MAPK signaling pathway in an experimental dry eye model, Curr Eye Res, 2010;35:165–75.
57. Li J, Roubeix C, Wang Y, et al., Therapeutic efficacy of trehalose eye drops for treatment of murine dry eye induced by an intelligently controlled environmental system, Mol Vis, 2012;18:317–29.
58. Dartt DA, Hodges RR, Li D, et al., Conjunctival goblet cell secretion stimulated by leukotrienes is reduced by resolvins D1 and E1 to promote resolution of inflammation, J Immunol, 2011;186:4455–66.
59. Lee CH, Resolvins as new fascinating drug candidates for inflammatory diseases, Arch Pharm Res, 2012;35:3–7.
60. de Paiva CS, Schwartz CE, Gjorstrup P, et al., Resolvin E1 (RX-10001) reduces corneal epithelial barrier disruption and protects against goblet cell loss in a murine model of dry eye, Cornea, 2012;31:1299–303.
61. Liu A, Ji J, Omega-3 essential fatty acids therapy for dry eye syndrome: a meta-analysis of randomized controlled studies, Med Sci Monit, 2014;20:1583–9.
62. Goyal S, Chauhan SK, Dana R, Blockade of prolymphangiogenic vascular endothelial growth factor C in dry eye disease, Arch Ophthalmol, 2012;130:84–9.
63. Stevenson W, Sadrai Z, Hua J, et al., Effects of topical Janus kinase inhibition on ocular surface inflammation and immunity, Cornea, 2014;33:177–83.
64. Murphy CJ, Bentley E, Miller PE, et al., The pharmacologic assessment of a novel lymphocyte function-associated antigen-1 antagonist (SAR 1118) for the treatment of keratoconjunctivitis sicca in dogs, Invest Ophthalmol Vis Sci, 2011;52:3174–80.
65. Semba CP, Swearingen D, Smith VL, et al., Safety and pharmacokinetics of a novel lymphocyte function-associated antigen-1 antagonist ophthalmic solution (SAR 1118) in healthy adults, J Ocul Pharmacol Ther, 2011;27:99–104.
66. Tong L, Lan W, Lim RR, et al., S100A proteins as molecular targets in the ocular surface inflammatory diseases, Ocul Surf, 2014;12:23–31.
Keywords: Dry eye disease, corneal damage, keratitis, variable signs, grading scheme, ciclosporin, case examples