Emerging Therapeutics for Ocular Surface Disease

Severe Central Nervous System and Respiratory Depression in a Neonate Following Accidental Oral Ingestion of Brimonidine Tartrate

Brimonidine is a third-generation alpha-2 adrenergic agonist and is classified as an ocular hypotensive agent. It is used for chronic glaucoma treatment by lowering intraocular pressure, crucial for preventing blindness. Brimonidine works by reducing aqueous humor production and increasing uveoscleral outflow. The improper use of brimonidine in children can result in severe adverse effects. If brimonidine eye drops are ingested orally, it can cause significant depression of the cardiorespiratory and central nervous systems. This is a case report of a 27-day-old neonate, who presented with central nervous system and respiratory depression after accidental ingestion of one drop of brimonidine tartrate ophthalmic solution. On arrival, he was having shallow breathing, a low Glasgow Coma Scale score, pinpoint pupils, and absent deep tendon reflexes. Gastric lavage was performed and supportive treatment was started. The patient showed gradual improvement and completely recovered within 48 hours.

Management of vernal keratoconjunctivitis: Navigating a changing treatment landscape

Vernal keratoconjunctivitis (VKC) is a chronic, progressive, and potentially sight-threatening form of ocular inflammatory disease that primarily affects children and young adults. Prevalence varies by region, ranging from <2 per 10,000 in the United States to as high as 1,100 per 10,000 in parts of Africa. The rarity of VKC in developed countries can make differential diagnosis challenging, and treatment is often delayed until the disease is advanced, and symptoms are significantly impacting patients' quality of life. Although once viewed primarily as an immunoglobulin E-mediated condition, approximately 50% of patients with VKC do not exhibit allergic sensitization. It is now recognized that the immunopathology of VKC involves multiple inflammatory pathways that lead to the signs, symptoms, and conjunctival eosinophilic and fibroproliferative lesions that are a hallmark of the disease. We examine the evolution of our understanding of the immunopathology of VKC, the expanding VKC treatment armamentarium, the clinical implications of emerging treatment approaches, and future directions for VKC research and practice.

Role of the ocular surface microbiome in allergic eye diseases

PURPOSE OF REVIEW

The purpose of this review is to provide an update on emerging literature on the role of the ocular surface microbiome (OSM) in allergic eye diseases.

RECENT FINDINGS

Findings in the literature suggest that the ocular surface microbiome plays a role in the pathophysiology and course of allergic disease of the ocular surface.

SUMMARY

Knowledge regarding the role of the ocular surface microbiome in allergic disease is important to guide development of targets for future therapeutic interventions.

The role of the topical nasal decongestant oxymetazoline as a novel therapeutic option for post-acne erythema: A split-face, double-blind, randomized, placebo-controlled trial

Post-acne erythema (PAE) is one of the most common sequelae of acne inflammation. Unfortunately, the treatment of PAE remains challenging due to limited effective topical treatments. The objectives of this study were to evaluate the efficacy and safety of topical oxymetazoline hydrochloride (OxH) 0.05% solution for PAE. This study was a split-face, participants-and investigators-blinded, randomized, placebo-controlled trial conducted between December 2021 and March 2022 in Bangkok, Thailand. Healthy adults aged from 18 to 45 years with mild to severe PAE, according to the Clinician's Erythema Assessment (CEA), on both sides of the face were eligible. After randomization, each participant applied the OxH to one side of their face and a placebo to the contralateral face twice daily for 12 weeks. The primary outcome was PAE lesion counts. The secondary outcomes were erythema index, clinical response rate at week 12 ("clear," "almost clear," or "at least two-grade improvement" by CEA), and patient satisfaction scores. A total of 30 participants were enrolled. The OxH-treated skin showed a significantly greater mean difference (MD) reduction in PAE lesion counts than the placebo after 8 weeks of treatment (4.30, 95% confidence interval [CI] 1.42-7.18). Similarly, the MD reduction of the erythema index was higher in the OxH-treated skin from the second week (11.82, 95% CI 8.48-15.15). Additionally, the OxH-treated side also achieved a higher clinical response rate after 8 weeks of treatment (40.00% vs. 6.67%; p = 0.002) and rated higher satisfaction than those using the placebo at the end of the study (mean [standard deviation] satisfaction score 8.30 [0.18] vs 7.40 [0.18], P < 0.001). There were no serious adverse events or flares of erythema during the study. In conclusion, our study demonstrated that the topical OxH 0.05% solution was effective, well-tolerated, and safe for reducing PAE without a rebound effect. It could be a choice of PAE management. Trial Registration: Thai Clinical Trials Registry No. TCTR20211207004.

Therapeutic Targets in Allergic Conjunctivitis

Allergic conjunctivitis (AC) is a common condition resulting from exposure to allergens such as pollen, animal dander, or mold. It is typically mediated by allergen-induced crosslinking of immunoglobulin E attached to receptors on primed conjunctival mast cells, which results in mast cell degranulation and histamine release, as well as the release of lipid mediators, cytokines, and chemokines. The clinical result is conjunctival hyperemia, tearing, intense itching, and chemosis. Refractory and chronic cases can result in ocular surface complications that may be vision threatening. Patients who experience even mild forms of this disease report an impact on their quality of life. Current treatment options range from non-pharmacologic therapies to ocular and systemic options. However, to adequately control AC, the use of multiple agents is often required. As such, a precise understanding of the immune mechanisms responsible for this ocular surface inflammation is needed to support ongoing research for potential therapeutic targets such as chemokine receptors, cytokine receptors, non-receptor tyrosine kinases, and integrins. This review utilized several published articles regarding the current therapeutic options to treat AC, as well as the pathological and immune mechanisms relevant to AC. This review will also focus on cellular and molecular targets in AC, with particular emphasis on potential therapeutic agents that can attenuate the pathology and immune mechanisms driven by cells, receptors, and molecules that participate in the immunopathogenesis and immunopathology of AC.

Current Knowledge in Allergic Conjunctivitis

Allergic conjunctivitis is a disease of increasing prevalence that affects both children and adults and causes significant deterioration of their quality of life and sometimes irreversible visual damage. There are various forms of the disease, some are allergen-induced such as seasonal and perennial allergic conjunctivitis, giant papillary conjunctivitis, and contact allergic blepharoconjunctivitis, whereas others are not always explained by allergen exposure, such as vernal keratoconjunctivitis and atopic keratoconjunctivitis. We review their clinical course, characteristics, and differential diagnosis, and highlight recent advances in their pathophysiology and treatment.

Research Progress of the Application of Hypothermia in the Eye

Hypothermia is widely used in the medical field to protect organs or tissues from damage. Different research fields have different explanations of the protection mechanism of hypothermia. Hypothermia is also widely used in the field of ophthalmology, for example, in the eye bank, the preservation of corneal tissue and the preservation of the eyeball. Low temperature can also be applied to some ophthalmic diseases, such as allergic conjunctivitis, retinal ischemia, and retinal hypoxia. It is used to relieve eye symptoms or reduce tissue damage. Hypothermic techniques have important applications in ophthalmic surgery, such as corneal refractive surgery, vitrectomy surgery, and ciliary body cryotherapy for end-stage glaucoma. Hypothermia can reduce the inflammation of the cornea and protect the retinal tissue. The eyeball is a complex organ, including collagen tissue of the eyeball wall and retinal nerve tissue and retinal blood vessels. The mechanism of low temperature protecting eye tissue is complicated. It is important to understand the mechanism of hypothermia and its applications in ophthalmology. This review introduces the mechanism of hypothermia and its application in the eye banks, eye diseases (allergic conjunctivitis, retinal ischemia, and hypoxia), and eye surgeries (corneal transplant surgery, corneal refractive surgery, and vitrectomy).

The spectrum of allergic ocular diseases

OBJECTIVE

The purpose of this article is to review the pathophysiologic mechanisms, differential diagnosis, evaluation, and treatment of the various manifestations of ocular allergy, with an especial focus on immunoglobulin E (IgE)-mediated disease.

DATA SOURCES

A PubMed search was performed to include articles, using the search terms ocular allergy and allergic conjunctivitis.

STUDY SELECTIONS

Recent and relevant human studies in the English language pertaining to our topic of study were selected. Animal studies pertaining to pathophysiology of ocular allergy were also reviewed. We focused on clinical trials, practice guidelines, reviews, and systematic reviews. In addition, case reports were reviewed if they described rare clinical presentations, disease mechanisms, or novel therapies.

RESULTS

Ocular allergy encompasses both IgE- and non-IgE-mediated disease, and the clinical severity may range from mild to sight-threatening inflammation. A comprehensive treatment regimen including education, lifestyle measures, topical therapies, and even systemic interventions may be necessary for the effective management of ocular allergies, tailored according to symptom severity.

CONCLUSION

Ocular allergy is frequently encountered by allergists and eye-care specialists, and despite progressively increasing incidence, it often remains underdiagnosed and, hence, untreated.

Allergic inflammation of the anterior surface of the eye

Background: Ocular allergies affect an estimated 40% of the population, 98% of which are because of allergic conjunctivitis and includes tear film dysfunction. With the current advent of both repurposed drugs for ocular allergies, as well as novel drugs, lubricants and methods of administration, there is a need to update new treatments to optimize the care of ocular allergy patients. Methods: An overview of mediators, clinical characteristics and management is provided in a summary format. Results: Lubricants (best when refrigerated provide immediate relief that is short lived (several minutes) due to its dilutional effect on mediators and pollen in the tear film. Immediate and longer-term benefit occurs from different topical and oral medications - primarily histamine receptor agonists. Conclusion: The newest prescription topical ophthalmic histamine H1 receptor antagonist (an inverse agonist) to be approved by the U.S. Food and Drug Administration in the past 10 years (U.S. NDA approved May 30, 2017) is cetirizine ophthalmic solution for the treatment of ocular itching with allergic conjunctivitis in adults and in children more than 2 years old.

Ocular allergy: update on clinical trials

PURPOSE OF REVIEW

The purpose of this article is to provide an update on the advances made through recent clinical trials regarding the treatment of the signs and symptoms of allergic conjunctivitis and its associated conditions.

RECENT FINDINGS

Recent studies have demonstrated significant advancement in the various forms of immunotherapy treatments. Nutritional interventions such as probiotics have surfaced as a viable complementary treatment option. Novel delivery methods such as contact lenses have been further studied along with a new tacrolimus formulation to improve ocular levels of the drug.

SUMMARY

Currently, the primary advances in treatment for allergic conjunctivitis has shifted from new ophthalmic agents to immunotherapy and improvement of drug delivery. This includes the classic subcutaneous and sublingual and the novel epicutaneous and intralymphatic immunotherapy delivery systems as well as an edible rice vaccine. New targets for treatment have spurred research into new antagonist drugs such as (OC000459), a prostaglandin D2 antagonist. The Marinosolv formulation using tacrolimus shows promise and may be considered for other ophthalmic agents in the future. Other nonpharmacological treatments such as stenting and mechanical barrier gel have demonstrated their usefulness in treating ocular symptoms.

Pharmacotherapeutic management of atopic keratoconjunctivitis

INTRODUCTION

Atopic keratoconjunctivitis (AKC) is a form of allergic eye disease that can have sight threating implications. Prevalence is underestimated due to scarce published data and treatment is expanding as a result of limitations of current strategies. This article aims to provide an up-to-date overview of AKC and summarize current and upcoming management.

AREAS COVERED

The authors provide history, immunopathogenesis, and summary of the clinical manifestations of AKC as well as presenting a review of the evidence in relation to treatment options including mast cell stabilizers, antihistamines, corticosteroids, and immunomodulatory drugs based on clinical trials. Future trends, drug targets, and novel delivery drug systems are also highlighted in this review.

EXPERT OPINION

Previously established treatment strategies of AKC had relied on corticosteroids, but the side effects of long-term therapy resulted in the expansion into the use of immunomodulatory drugs such as tacrolimus and ciclosporin. However, these too provide limited success due to the suboptimal structural properties of the current molecules. The ideal molecule should generate maximum permeability across the multi-layered structure of the cornea, be able to be formulated into eye drops for ease of application with minimal dosing and for maximal clinical effect.

Atopic Keratoconjunctivitis: Pharmacotherapy for the Elderly

Among the different forms of allergic conjunctivitis, atopic keratoconjunctivitis has distinct characteristics, defined by a more common onset in late adolescence or early adulthood, but also affecting the elderly, and with a higher prevalence in male individuals. However, the prevalence of atopic keratoconjunctivitis is scarcely investigated, and the data are often uncertain because other allergic nasal or respiratory disorders occur concomitantly. Mast cells, eosinophils, basophils, and T cells are involved in the pathogenesis of atopic keratoconjunctivitis. Despite its denomination as atopic, negative responses to skin tests or in-vitro immunoglobulin E tests are common. In fact, atopic keratoconjunctivitis can be attributed to a combination of T-helper-1 and T-helper-2 responses, but a higher prominence for T-helper-1 cells was found. The most common symptoms of atopic keratoconjunctivitis are bilateral ocular itching, burning, and tearing with a perennial presentation, although some patients may have seasonal exacerbations in winter or summer. Other symptoms such as photophobia, blurred vision, and mucous chewy discharge, owing to the accumulation of cells and mucin, may occur. The diagnosis of atopic keratoconjunctivitis is mainly clinical, as accepted diagnostic criteria or laboratory tests are not available. The treatment of atopic keratoconjunctivitis is aimed at controlling symptoms, decreasing relapse and exacerbations, and reducing vision loss. Therapeutic options comprise topical ophthalmic drops, including cromones, antihistamines, corticosteroids, and calcineurin inhibitors. Topical ointments are also available for corticosteroids and calcineurin inhibitors. Severe forms may require systemic medications including antihistamines, corticosteroids, and calcineurin inhibitors. Atopic keratoconjunctivitis therapy in the elderly does not differ from the adult population, but the occurrence of multi-morbidities and concomitant drug treatment, which are common in this age group, requires a careful evaluation to determine appropriate and personalized treatment.

The Role of Leukotrienes as Potential Therapeutic Targets in Allergic Disorders

Leukotrienes (LTs) are lipid mediators that play pivotal roles in acute and chronic inflammation and allergic diseases. They exert their biological effects by binding to specific G-protein-coupled receptors. Each LT receptor subtype exhibits unique functions and expression patterns. LTs play roles in various allergic diseases, including asthma (neutrophilic asthma and aspirin-sensitive asthma), allergic rhinitis, atopic dermatitis, allergic conjunctivitis, and anaphylaxis. This review summarizes the biology of LTs and their receptors, recent developments in the area of anti-LT strategies (in settings such as ongoing clinical studies), and prospects for future therapeutic applications.