Novel Extranasal Tear Stimulation: Pivotal Study Results

Efficacy and safety of trigeminal parasympathetic pathway stimulation for dry eye: A systematic review and meta-analysis

This study aimed to investigate the efficacy and safety of trigeminal parasympathetic pathway (TPP) stimulation in the treatment of dry eye. A comprehensive search for randomized clinical trials was performed in seven databases (MEDLINE, Embase, CENTRAL, etc.) up to 28 February 2023. After screening the suitable studies, the data were extracted and transformed as necessary. Data synthesis and analysis were performed using Review Manager 5.4, and the risk of bias and quality of evidence were evaluated with the recommended tools. Fourteen studies enrolling 1714 patients with two methods (electrical and chemical) of TPP stimulation were included. Overall findings indicate that TPP stimulation was effective in reducing subjective symptom score (standardized mean difference [SMD], -0.45; 95% confidence interval [CI], -0.63 to -0.28), corneal fluorescence staining (mean difference [MD], -0.78; 95% CI, -1.39 to -0.18), goblet cell area (MD, -32.10; 95% CI, -54.58 to -9.62) and perimeter (MD, -5.90; 95% CI, -10.27 to -1.53), and increasing Schirmer's test score (SMD, 0.98; 95% CI, 0.65 to 1.31) and tear film break-up time (SMD, 0.57; 95% CI, 0.19 to 0.95). Compared to inactive or low-activity stimulation controls, it has a higher incidence of adverse events. Therefore, TPP stimulation may be an effective treatment for dry eye, whether electrical or chemical. Adverse events are relatively mild and tolerable. Due to the high heterogeneity and low level of evidence, the current conclusions require to be further verified.

Novel treatments for dry eye syndrome

Dry eye syndrome (DES) is a prevalent and multifactorial disease that leads to a self-perpetuating cycle of inflammation and damage to the ocular surface. This results in symptoms such as redness, burning, and blurred vision, which can negatively affect a patient's quality of life. While treatments are available to manage DES, they only temporarily relieve symptoms. Furthermore, long-term use of certain medications can cause harm to the ocular surface. Therefore, there is a need for safer and effective treatments for DES. This review highlights the latest advancements in DES therapy, providing valuable insights into ongoing efforts to improve patient outcomes.

The Efficacy and Safety of Chinese Eye Exercise of Acupoints in Dry Eye Patients: A Randomized Controlled Trial

INTRODUCTION

Dry eye disorder (DED) is a growing global issue linked to excessive digital screen time. Chinese eye exercise of acupoint (CEA), a set of self-massages on shared Chinese acupuncture (CA), has been used to reduce visual-related ocular symptoms and possibly as an alternative treatment for DED. This study aimed to assess the efficacy and safety of CEA.

METHODS

A single-blind randomized controlled trial was conducted at Thammasat University Hospital in Thailand, recruiting 56 participants aged 20-60 years, equally divided into two groups: the treatment group with CEA and the control group with standard lid hygiene treatment (STD). The intervention program lasted 12 weeks.

MAIN OUTCOME MEASURES

Ocular Surface Disease Index (OSDI), tear break-up time (TBUT), Schirmer-I test (SIT), corneal surface staining (CSS), and self-recorded forms for safety and adverse effects were measured at baseline, week 4, and week 12. An independent sample t test, paired t test, and repeated measures (ANOVA) were used to compare results between both groups, study visits, and primary and secondary outcome measurements, respectively. The p values <0.05 were considered statistically significant.

RESULTS

The characteristics were not statistically different between both groups at the baseline. The mean OSDI scores were significantly reduced in both groups at week 4 and week 12 compared to baseline (p value <0.05). Additionally, both CEA and STD showed significant improvement in TBUT and SIT (p value <0.05). CSS was significantly improved only in the CEA groups (p value <0.05). No significant differences were observed between the study groups, except for SIT at week 12 (p value <0.05). For the safety, there were no adverse side effects in either group.

CONCLUSION

CEA seemed to be as effective as STD in improving the OSDI, TBUT, and SIT of DED without causing any side effects.

Einleitung

Das Trockene Auge (Dry eye disorder, DED) ist weltweit ein zunehmendes Problem, das mit übermässiger Bildschirmarbeit zusammenhängt. Die chinesische Augenübung der Akupunkturpunkte (Chinese eye exercise of acupoint, CEA), eine Reihe von Selbstmassagen an gemeinsamen CA-Akupunkturpunkten, wird zur Linderung visusbezogener Augensymptome und als mögliche alternative Behandlung für DED eingesetzt. Mit dieser Studie sollte die Wirksamkeit und Sicherheit von CEA bewertet werden.

Methoden

Am Thammasat-Universitätsklinikum in Thailand wurde eine einfach verblindete, randomisierte, kontrollierte Studie mit 56 Teilnehmern im Alter von 20 bis 60 Jahren durchgeführt, die zu gleichen Teilen zwei Gruppen zugewiesen wurden: die Behandlungsgruppe mit CEA und die Kontrollgruppe, die die Standard-Lidhygienebehandlung erhielt (STD). Das Interventionsprogramm dauerte 12 Wochen. Die Haupt-Zielkriterien, der Ocular Surface Disease Index (OSDI), die Tränenfilmaufreisszeit (tear break-up time, TBUT), der Schirmer-I-Test (SIT), das Corneal Surface Staining (CSS) und Selbstauskunftsformulare zur Sicherheit und zu unerwünschten Wirkungen wurden zu Beginn der Behandlung, in Woche 4 und in Woche 12 ermittelt. Für den Vergleich der Ergebnisse zwischen den beiden Gruppen, den Studienvisiten bzw. den primären und sekundären Zielkriterien wurden ein t Test für unabhängige Stichproben, ein t Test für paarige Stichproben und eine ANOVA mit Messwiederholungen verwendet. p-Werte <0,05 galten als statistisch signifikant.

Ergebnisse

Hinsichtlich der Merkmale bestand zwischen den beiden Gruppen kein statistischer Unterschied bei Studienbeginn. In beiden Gruppen fielen die mittleren OSDI-Scores in Woche 4 und Woche 12 im Vergleich zum Ausgangswert signifikant geringer aus (p-Wert <0,05). Darüber hinaus zeigten sowohl die CEA- als auch die STD-Gruppe eine signifikante Verbesserung der TBUT- und SIT-Werte (p-Wert <0,05). Das CSS verbesserte sich nur in der CEA-Gruppe signifikant (p-Wert <0,05). Zwischen den Studiengruppen waren keine signifikanten Unterschiede zu beobachten, ausser beim SIT in Woche 12 (p-Wert <0,05). Was die Sicherheit betrifft, so traten in beiden Gruppen keine unerwünschten Nebenwirkungen auf.

Schlussfolgerung

Die CEA schien die OSDI-, TBUT- und SIT-Werte bei DED ebenso wirksam zu verbessern wie die Standardbehandlung, ohne Nebenwirkungen zu verursachen.

Dry eye disease: identification and therapeutic strategies for primary care clinicians and clinical specialists

Dry eye disease (DED) is a multifactorial disorder characterized by loss of tear film homeostasis with an estimated worldwide prevalence of 5% to 50%. In DED, dysfunction of the ocular structures that create and regulate the tear film components-including the lacrimal glands, meibomian glands, cornea, and conjunctiva-causes a qualitative and/or quantitative tear deficiency with resultant tear film instability and hyperosmolarity. This initiates a vicious cycle of ocular surface inflammation and damage that may ultimately impair the quality of life and vision of affected patients. Many factors can contribute to the development of DED, including ocular and systemic diseases, topical and systemic medications, and environmental conditions. Because DED is a chronic disorder, treatment is most often long term and may utilize both pharmacologic and nonpharmacologic interventions to address all etiologic components. The long-term management of DED can be challenging and most often should involve eye care specialist referral. However, primary care clinicians (PCCs) are often the first points of contact for patients with DED and importantly provide initial diagnosis and preliminary patient education about the disease process. Consideration of DED is also vital for the practice of various specialties due to the large number of comorbidities and medications that can contribute to DED pathogenesis and progression. Therefore, it is important that PCCs and clinical specialists be aware of the etiology of DED and its available therapeutic options. This manuscript provides an overview of DED pathophysiology and treatment and discusses specific considerations regarding DED management for PCCs and clinical specialists.Key messagesSuccessful management of dry eye disease often requires the use of various pharmacologic and/or nonpharmacologic therapies, as well as environmental and lifestyle modifications, to mitigate the underlying etiologies and restore tear film homeostasis.Primary care clinicians play an essential role in dry eye disease management by establishing a diagnosis, educating patients about the disorder, and providing referrals to eye care specialists for initiation of specialized treatment and long-term follow-up.Primary care clinicians and clinical specialists should consider prescribing medications with fewer ocular surface effects whenever possible in patients at risk for or with existing dry eye disease.

Dry eye disease in astronauts: a narrative review

Long-duration spaceflight can have adverse effects on human health. One of the most common ocular conditions experienced by astronauts is dry eye disease (DED). Symptoms of DED include feelings of eye irritation, eye strain, foreign body sensation and blurred vision. Over 30% of International Space Station expedition crew members reported irritation and foreign body sensation. We reviewed the current literature on the prevalence and mechanisms of DED in astronauts and its potential implications for long-duration spaceflight, including the influence of environmental factors, such as microgravity and fluid shift on tear film physiology in space. DED has negative effects on astronaut performance, which is why there is a need for further research into the pathophysiology and countermeasures. As an in-flight countermeasure, neurostimulation seems to be among the most promising options.

Neurostimulation for dry eye disease

PURPOSE OF REVIEW

To review the neuroanatomy and physiology of the basal and reflex tearing and present the available and developing therapies using the concept of neurostimulation in dry eye disease (DED).

RECENT FINDINGS

The most prevalent current DED treatments seek to supplement low tear volume and tear components or reduce inflammation. Neurostimulation is a unique approach gaining momentum in recent years, geared toward increasing the production of all basal tear components by stimulating the nerves responsible for producing the various tear components. The neuroanatomy of the lacrimal unit provides several possible access points to stimulate tear production through two arms of the sensory trigeminal nerves. Modes of stimulation include chemical or energy in electrical or magnetic form. Research thus far has shown that neurostimulation can achieve lacrimal, goblet cell, and meibomian gland stimulation. Subjectively it improves symptoms of DED. Clinically, neurostimulation has improved the signs and symptoms of DED by increasing basal tear production and tear volume.

SUMMARY

Neurostimulation using electrical, mechanical, or chemical means is a novel concept to increase tear production and was demonstrated to be an effective, safe, and well-tolerated method for managing DED.

Updates in diagnostics, treatments, and correlations between oral and ocular manifestations of Sjogren's syndrome

Sjogren's syndrome (SS) is characterized as an autoimmune disorder targeting secretory glands, including the lacrimal and salivary glands, causing dry eye and dry mouth predominantly in women over the age of 40. In this review, we summarize recent advancements in SS diagnostics, treatments, and our understanding of correlations between oral and ocular manifestations of SS. Google Scholar and PubMed databases were utilized to search peer-reviewed papers since 2016 on SS diagnosis, treatment, and correlations between oral and ocular manifestations. For diagnostics, we discuss the updated SS classification criteria by the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR), new biomarkers, and compare studies of current diagnostic methods with alternative technologies. For treatments, we discuss topical, systemic, and surgical treatment developments in the management of oral and ocular symptoms of SS as there is still no cure for the disorder. Finally, we report studies that directly suggest correlations between the ocular surface disease and oral disease in SS, as well as shared abnormalities in the microbiome and cytokine expression that may be correlated. We conclude by stating limitations to our review as well as paths moving forward. Elucidating correlations between oral and ocular manifestations may be the key to furthering our understanding of SS pathogenesis as well as defining new standards for diagnosis and treatment.

Dry eye syndrome: comprehensive etiologies and recent clinical trials

Dry eye syndrome (DES) is multifactorial and likely to be a cause of concern more so than ever given the rapid pace of modernization, which is directly associated with many of the extrinsic causative factors. Additionally, recent studies have also postulated novel etiologies that may provide the basis for alternative treatment methods clinically. Such insights are especially important given that current approaches to tackle DES remains suboptimal. This review will primarily cover a comprehensive list of causes that lead to DES, summarize all the upcoming and ongoing clinical trials that focuses on treating this disease as well as discuss future potential treatments that can improve inclusivity.

Nicotinic acetylcholine receptor stimulation: A new approach for stimulating tear secretion in dry eye disease

Tear secretion is regulated by the lacrimal functional unit consisting of afferent and efferent nerve innervation. The afferent arm consists of trigeminal nociceptors on the ocular surface and nasal mucosa. When stimulated by agonists, nicotinic acetylcholine receptors on nerve endings in the nose initiate a reflex arc resulting in instantaneous tear secretion. Pharmacologic nasal neural stimulation to increase endogenous tear production is a novel approach to treating dry eye disease.

Dry eye disease, a prominent manifestation of systemic autoimmune disorders

OBJECTIVES

Dry eye disease (DED) is arguably the most frequent ocular disease encountered in ophthalmic clinical practice. DED is frequently an underestimated condition causing a significant impact on visual function and quality of life. Many systemic autoimmune diseases (SAIDs) are related to moderate to severe DED. The main objective of this review is to enhance the awareness among ophthalmologists of the potential association of an underlying SAID in a high-risk patient with DED.

METHODS

An exhaustive literature search was performed in the National Library of Medicine's Pubmed, Scopus, Web of Science, and Google Scholar databases for all English language articles published until November 2021. The main keywords included "dry eye disease" associated with autoimmune, connective tissue, endocrine, gastrointestinal, hematopoietic, vascular, and pulmonary diseases. Case reports, series, letters to the editor, reviews, and original articles were included.

RESULTS

Although DED is frequently associated with SAIDs, its diagnosis is commonly delayed or missed, producing significant complications, including corneal ulceration, melting, scleritis, uveitis, and optic neuritis resulting in severe complications detrimental to visual function and quality of life. SAID should be suspected in a woman, 30 to 60 years old with a family history of autoimmunity, presenting with DED symptoms and extraocular manifestations including arthralgias, dry mouth, unexplained weight and hair loss, chronic fatigue, heat or cold intolerance, insomnia, and mood disorders.

CONCLUSIONS

Establishing the correct diagnosis and treatment of DED associated with SAIDs is crucial to avoid its significant burden and severe ocular complications.

Stimulating Tear Production: Spotlight on Neurostimulation

Dry eye disease (DED) affects up to one-third of the global population. Traditional therapies, including topical lubricants, have been employed with variable success in the treatment of DED. Recently, neurostimulation of the lacrimal functional unit (LFU) has emerged as a promising alternative therapy for DED. In this review, we describe the neuroanatomical and pathophysiological considerations of DED and the LFU that make neurostimulation a viable therapeutic alternative. We further detail the various neurostimulatory approaches taken thus far—from implanted stimulators to external devices to chemical neurostimulation. Existing studies reveal the strengths of the neurostimulatory approach in increasing tear volume and improving dry eye symptoms, but further studies are needed to elucidate its true potential in treatment of DED.

Alternative therapies for dry eye disease

PURPOSE OF REVIEW

Dry eye disease (DED) is a multifactorial disease affecting approximately 5-50% of individuals in various populations. Contributors to DED include, but are not limited to, lacrimal gland hypofunction, meibomian gland dysfunction (MGD), ocular surface inflammation, and corneal nerve dysfunction. Current DED treatments target some facets of the disease, such as ocular surface inflammation, but not all individuals experience adequate symptom relief. As such, this review focuses on alternative and adjunct approaches that are being explored to target underlying contributors to DED.

RECENT FINDINGS

Neuromodulation, stem cell treatments, and oral royal jelly have all been studied in individuals with DED and lacrimal gland hypofunction, with promising results. In individuals with MGD, devices that provide eyelid warming or intense pulsed light therapy may reduce DED symptoms and signs, as may topical Manuka honey. For those with ocular surface inflammation, naturally derived anti-inflammatory agents may be helpful, with the compound trehalose being farthest along in the process of investigation. Nerve growth factor, blood-derived products, corneal neurotization, and to a lesser degree, fatty acids have been studied in individuals with DED and neurotrophic keratitis (i.e. corneal nerve hyposensitivity). Various adjuvant therapies have been investigated in individuals with DED with neuropathic pain (i.e. corneal nerve hypersensitivity) including nerve blocks, neurostimulation, botulinum toxin, and acupuncture, although study numbers and design are generally weaker than for the other DED sub-types.

SUMMARY

Several alternatives and adjunct DED therapies are being investigated that target various aspects of disease. For many, more robust studies are required to assess their sustainability and applicability.