Ocular allergy

Applications of topical immunomodulators enhance clinical signs of vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC): a meta-analysis

PURPOSE

This meta-analysis aimed to review the safety and efficacy of topical cyclosporine A (CsA) and topical tacrolimus in allergic eye disease.

METHODS

A systematic search identified thirteen studies and a total of 445 patients for inclusion, making this the largest meta-analysis published on the subject. The current review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Thirteen randomized control trials were included in the meta-analysis. Eleven studies used CsA as the treatment, and two used Tacrolimus. In total, 445 participants were included, of whom 76.6% were male. The mean age of participants across the included studies was 14 years. All studies reported clinical signs as evaluated by an examining clinician. Signs were usually assessed by anatomical region, with the most common regions being the conjunctiva and the cornea, and the most common signs assessed were hyperemia and papillae. Three studies accounted for more than 50% of the meta-analysis's weight. Effect size (d) ranged from - 2.37 to - 0.03, negative values favoring immunomodulators. Fixed Effect Meta-Analysis returned an SMD of - 0.81 (95% CI [- 0.98, - 0.65]). However, there was significant heterogeneity (I2 = 61%, Qw = 30.76) in the outcome measure (P = 0.0021); therefore, a random-effect meta-analysis was also completed in which the pooled SMD was - 0.98 (95% CI [- 1.26, - 0.69], τ2 = 0.16).

CONCLUSIONS

This study affirms the current scientific community's stance that immunomodulators effectively treat clinical signs, including blepharitis, conjunctival hyperemia, edema, papillae, and corneal damage in severe ocular allergic disease.

Presentation, diagnosis, and the role of subcutaneous and sublingual immunotherapy in the management of ocular allergy

Allergic eye disease or ocular allergy is a debilitating condition with a significant impact on quality of life and productivity. As atopy continues to be on the rise, primary care providers are likely to encounter increasing numbers of patients with allergic eye disease. This review outlines the classification and pathophysiology of allergic eye disease and its clinical presentation. This paper does not detail traditional first-line therapies of allergic eye disease but describes the interdisciplinary management between the eye-care provider and allergist. It is recommended that patients with ongoing signs and symptoms of ocular allergy despite first-line therapies be referred for allergen immunotherapy, as it is highly effective for treatment of allergic eye disease. Through induction of immune tolerance, allergen immunotherapy is a disease-modifying therapy that can result in long-term improvement of ocular allergy. A thorough literature review was conducted on the efficacy and safety of allergen immunotherapy, including subcutaneous immunotherapy and sublingual immunotherapy, and its role in allergic eye disease.

Chemokines in allergic conjunctivitis

PURPOSE OF REVIEW

Chemokines are a large group of low molecular weight cytokines that attract and activate leukocytes throughout the body and therefore have a key role in the framework of late-phase allergic responses. The purpose of this article is to provide an overview of the main chemokines involved in allergic conjunctivitis, their primary functions and their physiological roles, and therapies targeted at chemokines and their receptors for ocular allergic diseases.

RECENT FINDINGS

In recent years, there have been considerable advances in the understanding of ocular pathophysiology of ocular surface inflammatory diseases including both allergic eye diseases and dry eye syndrome. Several therapies being developed for dry eye inflammation are recognized as possible therapies for ocular allergic diseases as there are often common chemokines involved in both disease spectra.

SUMMARY

Chemokines represent an integral part of the late-phase cascade of ocular allergic inflammation. A deep understanding of specific chemokines and their interactions will help in targeting therapies to effectively manage ocular clinical findings and symptoms of allergic eye disease.

A contemporary look at allergic conjunctivitis

Allergic eye disease is common, yet often overlooked in North America. In the U.S., up to 40% of the population is deemed to be affected and this number is growing. Symptoms and signs of ocular allergy can lead to decreased productivity and negatively impact quality of life (QoL). Various treatment options exist to achieve symptom control. For allergic conjunctivitis, ophthalmic agents include antihistamines, mast cell stabilizers, dual-activity agents, nonsteroidal anti-inflammatory drugs (NSAIDs), steroids and some off-label treatments. Immunotherapy is recommended as a therapeutic option. This review provides a summary of the forms of ocular allergies, with a focus on symptoms and signs, impact on QoL, physical examination, diagnosis and therapeutic options of allergic conjunctivitis. Through multidisciplinary collaborations, a simplified algorithm for the treatment of allergic conjunctivitis is proposed for Canadian clinical practice.

Topical cis-urocanic acid prevents ocular surface irritation in both IgE -independent and -mediated rat model

PURPOSE

Our purpose was to investigate the effect of locally administered cis-urocanic (cis-UCA) in two experimental models of allergic conjunctivitis.

METHODS

The compound 48/80 (C48/80)-induced ocular irritation model (IgE-independent) and the ovalbumin (OA)-induced ocular allergy model (IgE-mediated) were used to test and compare the effect of cis-UCA on dexamethasone, ketotifen and olopatadine. In the C48/80 model, clinical severity scoring from photographs, immunohistochemical analysis of nuclear Ki-67 antigen to quantify actively proliferating epithelial cells and of caspase-3 enzyme to identify apoptotic activity in the conjunctival tissue were used. In the OA model, an Evans Blue stain concentration of conjunctival tissue was used to evaluate vascular leakage due to allergic reaction.

RESULTS

The cis-UCA was well tolerated and effective in both the IgE-independent and -mediated rat models. Treatment with C48/80 caused conjunctival hyperaemia, which was significantly inhibited by ketotifen at the 6 h time point (p = 0.014) and by dexamethasone and cis-UCA 0.5% at 12 (p = 0.004) and 24 (p = 0.004) hour time points. In a comparison between the active drug treatments, only ketotifen showed a significant difference (p = 0.023) to cis-UCA treatment at the 1 h time point, otherwise there were no statistically significant differences between the active drugs. Ketotifen, dexamethasone and cis-UCA 0.5% significantly inhibited the C48/80-induced nuclear accumulation of Ki-67, without differences between the active treatment groups. In the OA model, cis-UCA 0.5% did not inhibit the vascular leakage of conjunctiva, whereas cis-UCA 2.5% of was at least equally effective compared to olopatadine, abolishing the allergic vascular leakage response almost completely.

CONCLUSIONS

The present findings in the two AC models suggest that cis-UCA might have anti-allergic potency both in immediate and delayed-type allergic reactions in the eye.

Efficacy of olopatadine hydrochloride 0.1%, emedastine difumarate 0.05%, and loteprednol etabonate 0.5% for Chinese children with seasonal allergic conjunctivitis: a randomized vehicle-controlled study

Background

Allergic conjunctivitis (AC) is a disease of various agents that affects the physical and mental health of children. Although the most effective therapy has not been found so far, it is essential to explore the considerable therapeutic method. We compared the clinical efficacy of olopatadine, emedastine, loteprednol etabonate (LE), and vehicle for treating seasonal allergic conjunctivitis (SAC) in Chinese children.

Methods

Eighty cases of 160 eyes aged from 5 to 10 years with SAC were available and those subjects were randomly distributed into 4 groups. Both their eyes received olopatadine hydrochloride 0.1% twice a day, emedastine difumarate 0.05% twice a day, or LE 0.5% 4 times a day, respectively, whereas those of the control group received artificial tears (AT) 0.5% 3 times a day. This study was conducted successfully and the observations were collected before treatment and on day 8 (±1 day) and day 15 (±2 days) afterward. The principal measurement of efficacy was focused on the signs and symptoms of the subjects, evaluated before and after treatment, in addition to visual acuity (VA) and fundus oculi.

Results

On day 8 (±1 day) and day 15 (±2 days), all the antiallergic agents were found to be more effective than vehicle (p < 0.05) in terms of all the symptoms and signs. However, there was no statistical significance (p ≥ 0.05) shown among the treatment groups. There were no evident changes in VA and no clinically significant changes were observed in fundus oculi.

Conclusion

After the treatment, the efficacy presented a similar distribution among the trial groups.

Knowledge and awareness of ocular allergy among undergraduate students of public universities in Ghana

BACKGROUND

Ocular allergy is a growing public health problem that greatly impacts the day-to-day life of sufferers and their families. Other aspects of their activities of daily living such as schooling, professional, and social life are affected hence an increased awareness and knowledge of ocular allergies, their detection and treatment is paramount. This study was to assess the level of knowledge and awareness of ocular allergy among undergraduate students of public universities in Ghana.

METHODS

A descriptive cross sectional survey was conducted among 1000 students from three selected public universities in Ghana. Each respondent completed a questionnaire that had questions concerning awareness and knowledge of ocular allergy.

RESULTS

Out of the 1000 students, 347 (34.7 %) were aware of ocular allergy. Of these 347 students, the level of knowledge of ocular allergy was generally low. Majority of the students had their source of information about ocular allergy from the media and the internet. There was statistical significant association among awareness of ocular allergy, sources of information and programme of study (p < 0.001).

CONCLUSION

Level of awareness among university students is generally low. Students' programmes of study influenced their knowledge of ocular allergy. Public health measures are recommended to help educate students on the prevention and control of ocular allergy as well as the complications associated with this condition.

Topical immunomodulators in the management of allergic eye diseases

PURPOSE OF REVIEW

Allergic eye diseases comprise a spectrum of diseases, with each condition being characterized by a complex immunopathology. The more severe and chronic conditions, such as vernal keratoconjunctivitis and atopic keratoconjunctivitis, involve predominantly mast cells and eosinophils, while also being associated with a preponderance of T cells. Treatment with topical antihistamines or mast cell stabilizers is often unsatisfactory, and therapy depends on topical corticosteroids. Corticosteroids have significant side-effects with long-term use; therefore, they appear to be more appropriate for short-term pulse therapy. Immunomodulatory agents can also be used to inhibit T-cell activation and show encouraging results among patients with severe allergic eye conditions. The present review is an attempt to present a coherent picture of the recent investigations of topical immunomodulatory agents' therapy in severe allergic eye diseases, especially cyclosporine A and tacrolimus, and their mechanisms of action.

RECENT FINDINGS

Immunomodulatory agents are commonly indicated for the treatment of severe and prolonged allergic conjunctivitis. This article reviews the recent studies of these drugs and the development of immunomodulatory treatments for severe allergic eye diseases.

SUMMARY

Cyclosporine A and tacrolimus are currently available for the treatment of severe allergic conjunctivitis. These agents have led to improved therapeutic results for patients with severe and chronic allergic eye diseases.

Changes in sensory activity of ocular surface sensory nerves during allergic keratoconjunctivitis

Peripheral neural mechanisms underlying the sensations of irritation, discomfort, and itch accompanying the eye allergic response have not been hitherto analyzed. We explored this question recording the changes in the electrical activity of corneoconjunctival sensory nerve fibers of the guinea pig after an ocular allergic challenge. Sensitization was produced by i.p. ovalbumin followed by repeated application in the eye of 10% ovalbumin on days 14 to 18. Blinking and tearing rate were measured. Spontaneous and stimulus-evoked (mechanical, thermal, chemical) impulse activity was recorded from mechanonociceptor, polymodal nociceptor and cold corneoscleral sensory afferent fibers. After a single (day 14) or repeated daily exposures to the allergen during the following 3 to 4days, tearing and blinking rate increased significantly. Also, sensitization was observed in mechanonociceptors (transient reduction of mechanical threshold only on day 14) and in polymodal nociceptors (sustained enhancement of the impulse response to acidic stimulation). In contrast, cold thermoreceptors showed a significant decrease in basal ongoing activity and in the response to cooling. Treatment with the TRPV1 and TRPA1 blockers capsazepine and HC-030031 reversed the augmented blinking. Only capsazepine attenuated tearing rate increase and sensitization of the polymodal nociceptors response to CO2. Capsazepine also prevented the decrease in cold thermoreceptor activity caused by the allergic challenge. We conclude that changes in nerve impulse activity accompanying the ocular allergic response, primarily mediated by activation of nociceptor's TRPV1 and to a lesser degree by activation of TRPA1 channels, explain the eye discomfort sensations accompanying allergic episodes.