Évaluation de l’efficacité du Nutrilarm®, complément nutritionnel à base d’acides gras essentiels polyinsaturés oméga 3 et oméga 6, versus placebo chez des patients atteints de sécheresse oculaire bilatérale modérée et traitée

The efficacy and safety of varenicline nasal spray for the management of dry eye signs: a systematic review and meta-analysis

BACKGROUND

Dry eye disease (DED) is caused by a persistently unstable tear film leading to ocular discomfort and is treated mainly with tear supplementation. There is emerging evidence that nicotinic acetylcholine receptor (nAChR) agonists (e.g., varenicline and simpinicline) nasal sprays are effective for DED. Our systematic review and meta-analysis assessed the efficacy and safety of varenicline nasal spray (VNS) for DED treatment.

METHODS

The Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched. Only randomized controlled trials (RCTs) that evaluated the efficacy of VNS versus placebo were included. The efficacy endpoint was the mean change in the anesthetized Schirmer test score (STS), a measure of basal tear production, from baseline. The safety endpoints were serious adverse events (SAEs) and adverse events (AEs). The standardized mean difference (SMD) was used for continuous outcomes, while the risk ratio (RR) was used to demonstrate dichotomous variables. The certainty of the evidence was rated utilizing the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. The risk of bias assessment was conducted using the Revised Cochrane risk of bias tool for randomized trials.

RESULTS

Three RCTs (n = 1063) met the eligibility criteria. All RCTs had a low risk of bias. The meta-analysis found a statistically significant increase in the mean STS change from baseline on day 28. The pooled analysis found no significant difference between VNS and placebo in the frequency of SAEs and ocular AEs. However, VNS had a significant effect on developing nasal cavity-related AEs.

CONCLUSION

VNS caused a highly significant improvement regarding the efficacy endpoint but caused an increased frequency of some nasal cavity-related AEs (i.e., cough and throat irritation). However, it caused neither SAEs nor ocular AEs. Included studies had a low risk of bias.

Oxidative Stress in the Protection and Injury of the Lacrimal Gland and the Ocular Surface: are There Perspectives for Therapeutics?

Oxidative stress (OS) is a major disruption in the physiology of the lacrimal functional unit (LFU). Antioxidant enzymes have dual protective activities: antioxidant and antimicrobial activities. Peroxidases have been indistinctly used as markers of the secretory activity of the LFU and implicated in the pathophysiology, diagnosis and treatment of dry eye disease (DED), even though they comprise a large family of enzymes that includes lactoperoxidase (LPO) and glutathione peroxidase (GPO), among others. Assays to measure and correlate OS with other local LFU phenomena have methodological limitations. Studies implicate molecules and reactions involved in OS as markers of homeostasis, and other studies identify them as part of the physiopathology of diseases. Despite these conflicting concepts and observations, it is clear that OS is influential in the development of DED. Moreover, many antioxidant strategies have been proposed for its treatment, including calorie restriction to nutritional supplementation. This review offers a critical analysis of the biological mechanisms, diagnostic outcomes, drug use, dietary supplements, and life habits that implicate the influence of OS on DED.

The Protective Effect of Polyunsaturated Fatty Acids against Dry Eye Disease: A Literature Review

Dry eye disease (DED) is a common disease, and have an adverse effect the physical, functional, and psychological quality of life. It is a multifactorial disorder characterized by the loss of tear film homeostasis, in which self-perpetuating vicious cycle leads to deterioration of function and inflammation of the lacrimal functional unit. Hence, treatment strategies should be aimed at the interruption of the vicious inflammatory cycle and alleviation of ocular surface inflammation. Anti-inflammatory therapies have been shown to improve the signs and symptoms of the disease. Evidence indicates that polyunsaturated fatty acids (PUFAs) may contribute to reinforcement of innate anti-inflammatory mechanisms, and systemic and topical administration of PUFAs may help modulate ocular surface inflammation. In the present review, the authors will introduce the results of clinical and experimental studies to elucidate the mechanism, efficacy, and safety of systemic and topical supplementation with PUFAs as an alternative therapeutic strategy for DED. This review will also include discussion regarding current perspectives, including evidence-based recommendations and possible side effects of PUFAs supplementation. The review of the literature suggests that PUFAs supplementation can be a viable option for the treatment of DED, although further studies are needed for establishment of treatment guidelines.

Omega-3 and omega-6 polyunsaturated fatty acids for dry eye disease

BACKGROUND

Polyunsaturated fatty acid (PUFA) supplements, involving omega-3 and/or omega-6 components, have been proposed as a therapy for dry eye. Omega-3 PUFAs exist in both short- (alpha-linolenic acid [ALA]) and long-chain (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) forms, which largely derive from certain plant- and marine-based foods respectively. Omega-6 PUFAs are present in some vegetable oils, meats, and other animal products.

OBJECTIVES

To assess the effects of omega-3 and omega-6 polyunsaturated fatty acid (PUFA) supplements on dry eye signs and symptoms.

SEARCH METHODS

CENTRAL, Medline, Embase, two other databases and three trial registries were searched in February 2018, together with reference checking. A top-up search was conducted in October 2019, but the results have not yet been incorporated.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) involving dry eye participants, in which omega-3 and/or omega-6 supplements were compared with a placebo/control supplement, artificial tears, or no treatment. We included head-to-head trials comparing different forms or doses of PUFAs.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 34 RCTs, involving 4314 adult participants from 13 countries with dry eye of variable severity and etiology. Follow-up ranged from one to 12 months. Nine (26.5%) studies had published protocols and/or were registered. Over half of studies had high risk of bias in one or more domains. Long-chain omega-3 (EPA and DHA) versus placebo or no treatment (10 RCTs) We found low certainty evidence that there may be little to no reduction in dry eye symptoms with long-chain omega-3 versus placebo (four studies, 677 participants; mean difference [MD] -2.47, 95% confidence interval [CI] -5.14 to 0.19 units). We found moderate certainty evidence for a probable benefit of long-chain omega-3 supplements in increasing aqueous tear production relative to placebo (six studies, 1704 participants; MD 0.68, 95% CI 0.26 to 1.09 mm/5 min using the Schirmer test), although we did not judge this difference to be clinically meaningful. We found low certainty evidence for a possible reduction in tear osmolarity (one study, 54 participants; MD -17.71, 95% CI -28.07 to -7.35 mOsmol/L). Heterogeneity was too substantial to pool data on tear break-up time (TBUT) and adverse effects. Combined omega-3 and omega-6 versus placebo (four RCTs) For symptoms (low certainty) and ocular surface staining (moderate certainty), data from the four included trials could not be meta-analyzed, and thus effects on these outcomes were unclear. For the Schirmer test, we found moderate certainty evidence that there was no intergroup difference (four studies, 455 participants; MD: 0.66, 95% CI -0.45 to 1.77 mm/5 min). There was moderate certainty for a probable improvement in TBUT with the PUFA intervention relative to placebo (four studies, 455 participants; MD 0.55, 95% CI 0.04 to 1.07 seconds). Effects on tear osmolarity and adverse events were unclear, with data only available from a single small study for each outcome. Omega-3 plus conventional therapy versus conventional therapy alone (two RCTs) For omega-3 plus conventional therapy versus conventional therapy alone, we found low certainty evidence suggesting an intergroup difference in symptoms favoring the omega-3 group (two studies, 70 participants; MD -7.16, 95% CI -13.97 to -0.34 OSDI units). Data could not be combined for all other outcomes. Long-chain omega-3 (EPA and DHA) versus omega-6 (five RCTs) For long-chain omega-3 versus omega-6 supplementation, we found moderate certainty evidence for a probable improvement in dry eye symptoms (two studies, 130 participants; MD -11.88, 95% CI -18.85 to -4.92 OSDI units). Meta-analysis was not possible for outcomes relating to ocular surface staining, Schirmer test or TBUT. We found low certainty evidence for a potential improvement in tear osmolarity (one study, 105 participants; MD -11.10, 95% CI -12.15 to -10.05 mOsmol/L). There was low level certainty regarding any potential effect on gastrointestinal side effects (two studies, 91 participants; RR 2.34, 95% CI 0.35 to 15.54).

AUTHORS' CONCLUSIONS

Overall, the findings in this review suggest a possible role for long-chain omega-3 supplementation in managing dry eye disease, although the evidence is uncertain and inconsistent. A core outcome set would work toward improving the consistency of reporting and the capacity to synthesize evidence.

Effects of Polyunsaturated Fatty Acids on Nonspecific Typical Dry Eye Disease: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

To investigate the effects of polyunsaturated fatty acids (PUFAs) in patients with dry eye disease (DED), a multifactorial inflammatory disorder, we searched Cochrane Library, EMBASE, PubMed, and Web of Science for randomized clinical trials (RCTs) investigating the effect of PUFAs in patients with DED before March 2019. Two reviewers independently abstracted data of tear breakup time (TBUT), Schirmer’s test, osmolarity, and ocular surface disease index (OSDI). We conducted pairwise meta-analysis using means and standard deviations (SDs) in a random-effects model for continuous outcomes. Thirteen eligible RCTs with 1782 patients with nonspecific typical DED were included. Patients who received PUFA treatment without other eye medications exhibited greater improvements in TBUT (MD = 1.80; p = 0.001), Schirmer test scores (MD = 0.50; p < 0.001), osmolarity (MD = −15.95; p < 0.001), and OSDI scores (MD = −10.19; p < 0.001) than those who received placebo treatment. However, the effects of PUFAs on TBUT (p < 0.001) and OSDI scores (p = 0.03) weakened with treatment duration. PUFAs are effective in treating nonspecific typical DED, particularly as a short-term treatment, with relatively few adverse events. Therefore, in real-world clinical practice, PUFA supplements are worth being suggested to patients with nonspecific typical DED who are not concurrently using other topical or systematic eye medications.

The Effect of Periocular Fatty Acids and 0.15% Hyaluronate Eye Drops Application on Keratoconjunctivitis Sicca in Dogs: An Exploratory Study

The aim of this exploratory study was to evaluate the efficacy of a periophthalmic cream of a pool of fatty acids (FAG®) in association with 0.15% hyaluronate eye drops in alleviating the clinical symptoms of keratoconjunctivitis sicca (KCS) in a case series of dogs. The study was conducted on 10 dogs diagnosed with idiopathic KCS. All dogs had been previously treated with topical tobramycin alone, which had been ineffective in improving clinical signs. The affected eyes were treated with 2 applications daily of a periophthalmic cream of FAG® and 1 drop 3 times a day of 0.15% of hyaluronate eye drops for 8 weeks. Schirmer tear test I (STT I) values were recorded and ocular signs (conjunctival hyperemia, ocular discharge, corneal opacity, vascularization and pigmentation, and discomfort level) were collected, scored on a 3-point scale (grade 0, grade 1, and grade 2). Differences between scores and STT data recorded at baseline and at 8 weeks of therapy were statistically analysed. The effect of treatment was pronounced (increase in STT values by more than 4 mm/min, no signs of inflammation) in 8/18 eyes; moderate (increase in STT values of 3-4 mm/min or mild improvement in signs of corneal/conjunctival inflammation) in 3/18 eyes; and unsatisfactory in 7 of 18 eyes. Median of STT values significantly improved compared with baseline levels, while statistically significant decreases in clinical-sign scores of conjunctival hyperemia, ocular discharge, and discomfort were recorded. However, in moderate and advanced stages, reduction of neovascularization or corneal pigmentation was not observed throughout the treatment period. No noticeable adverse reactions were recorded. Preliminary results indicate that the application of periocular FAG and topical 0.15% hyaluronate eye drops may be a suitable treatment for KCS in dogs in selected cases. A larger comparative study is necessary to further confirm these findings.

[Ocular surface aging: Pathophysiology and consequences for management]

All the components of the ocular surface and the lacrimal system are affected by aging. Aging induces lacrimal gland fibrosis, Meibomian gland dysfunction, loss of corneal sensitivity, decreased corneal cell density, impairment of immune defences, increased local inflammation associated with hormonal changes, conjunctivochalasis, lid abnormalities, etc. Furthermore, homeostasis of the ocular surface may be altered by various age-related systemic comorbidities and iatrogenic interventions. Altogether, aging is considered the most predominant risk factor for dry eye disease. The increasing knowledge of the pathophysiology of aging of the ocular surface allows for refinement of the management of ocular surface disease in the elderly.

Efficacy of nutritional supplementation with omega-3 and omega-6 fatty acids in dry eye syndrome: a systematic review of randomized clinical trials

PURPOSE

To critically appraise scientific evidence regarding the efficacy of nutritional supplementation with omega-3 and omega-6 fatty acids for the treatment of dry eye syndrome (DES).

METHODS

A systematic review of randomized clinical trials was performed. Two independent reviewers selected and analysed the scientific papers that met inclusion and exclusion criteria. Objective and subjective efficacy outcomes were assessed.

RESULTS

The trials involved a total of 2591 patients in fifteen independent studies. All studies were published between 2005 and 2015. The supplements used were mostly omega-3 and omega-6 in different proportions. Subjective improvement was measured using mainly Ocular Surface Disease Index (OSDI) test and Dry Eye Severity Score (DESS) test: significant differences in favour of the experimental group were found in seven of the studies. The objective amelioration was assessed by lacrimal function parameters: Tear break-up time (TBUT) significantly increased in nine studies and Schirmer's test in four studies.

CONCLUSION

We observed a discrete improvement in the parameters of tear function. Scientific evidence is not strong enough to systematically recommend the use of omega-3 and omega-6 fatty acids as a standalone treatment of DES independently from its aetiology. However, they could be considered as an effective alternative to topical treatment in patients with DES secondary to certain pathologies.