Vernal keratoconjunctivitis in twins: case report and literature review

Diagnostic criteria of chronic conjunctivitis: atopic keratoconjunctivitis and vernal keratoconjunctivitis

PURPOSE OF REVIEW

Chronic ocular allergies, vernal (VKC) and atopic keratoconjunctivitis (AKC) are relatively rare conditions that require definite diagnostic criteria to the most appropriate therapeutical approach.

RECENT FINDINGS

The diagnosis of both VKC and AKC is generally based on clinical history, signs and symptoms, and the results of allergic tests, which allow to identify the different diseases phenotypes. However, other subtypes of the two diseases and/or overlaps may occur making the diagnosis non always so clear, such as VKC and AKC overlaps or adult-like VKC disease. Each of these phenotypes may be sustained by different mechanisms which are still not well defined but not only related to a type 2 inflammation. The further challenges will be to correlate clinical or molecular biomarkers to a single subtype or disease severity.

SUMMARY

Definite criteria of chronic allergies will further guide to more specific therapeutical approaches.

Genetic predisposition to ocular surface disorders and opportunities for gene-based therapies

The ocular surface, comprised of the corneal and conjunctival epithelium, innervation system, immune components, and tear-film apparatus, plays a key role in ocular integrity as well as comfort and vision. Gene defects may result in congenital ocular or systemic disorders with prominent ocular surface involvement. Examples include epithelial corneal dystrophies, aniridia, ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome, xeroderma pigmentosum (XP), and hereditary sensory and autonomic neuropathy. In addition, genetic factors may interact with environmental risk factors in the development of several multifactorial ocular surface disorders (OSDs) such as autoimmune disorders, allergies, neoplasms, and dry eye disease. Advanced gene-based technologies have already been introduced in disease modelling and proof-of-concept gene therapies for monogenic OSDs. For instance, patient-derived induced pluripotent stem cells have been used for modelling aniridia-associated keratopathy (AAK), XP, and EEC syndrome. Moreover, CRISPR/Cas9 genome editing has been used for disease modelling and/or gene therapy for AAK and Meesmann's epithelial corneal dystrophy. A better understanding of the role of genetic factors in OSDs may be helpful in designing personalized disease models and treatment approaches. Gene-based approaches in monogenic OSDs and genetic predisposition to multifactorial OSDs such as immune-mediated disorders and neoplasms with known or possible genetic risk factors has been seldom reviewed. In this narrative review, we discuss the role of genetic factors in monogenic and multifactorial OSDs and potential opportunities for gene therapy.

The effect of COVID-19 imposed lockdown on Italian children with Vernal Keratoconjunctivitis

Background

Vernal keratoconjunctivitis (VKC) is a chronic, inflammatory-allergic disease of the cornea and conjunctiva. Environmental factors, such as light exposure, have been supposed to play a role in the pathogenesis of ocular inflammation and in the worsening of VKC.

Objective

The aim of this study was to estimate the impact of reduced sunlight exposure in patients with VKC during the imposed lockdown period for the SARS-CoV-2 pandemic emergency.

Methods

We retrospectively reviewed data of patients with VKC visited during spring season in 2020 and 2019 at Vernal Keratoconjunctivitis Multidisciplinar Outpatient of our Hospital.

Subjective symptoms were evaluated by Visual analogue scale (VAS) and VKC severity was graded by Bonini scale. Quality of life was evaluated by Correlations of Quality of Life in Children with Vernal Keratoconjunctivitis (QUICK) questionnaire. The number of hours of e-learning as well as of hours spent in front of a bright screen (PC, TV, mobile, tablet play station, and so on) was also investigated.

Results

Twenty-nine male subjects (mean ± SD age: 8.74 ± 2.40 years) with VKC were included in the study. Most of the patients (17/29) were sensitized individuals.

No significant changes in Bonini severity score and in VAS evaluation were observed comparing 2020 to 2019 values. Ten (34.4%) patients did benefit from the reduced sunlight exposure. The increased use of bright screens was associated with worsening of VKC severity.

Conclusions

Sunlight exposure plays a role in VKC exacerbation in about one third of patients. The number of hours spent in front of bright screens may influence severity of VKC symptoms.

Understanding Vernal Keratoconjunctivitis: Beyond Allergic Mechanisms

Vernal keratoconjunctivitis (VKC) is a chronic, recurrent, inflammatory disease of the cornea and conjunctiva mostly affecting boys in prepubertal age. VKC recurrence is characterized by intense symptoms of itching, redness, and photophobia associated with corneal damage, impairment of visual function, and quality of life. The pathogenesis of VKC has not yet been completely understood, and it is still controversial. In fact, VKC is considered an ocular allergic disease due to the involvement of immunoglobulin E, eosinophils, and mast cells, and of a lymphocyte T-helper type 2 reaction. However, approximately half of VKC patients have negative allergological history and testing, suggesting that other pathogenic mechanisms participate in VKC development and severity. Specifically, evidence suggests that genetic, endocrine, neuronal factors and an imbalance of innate immunity are involved in the pathogenesis of VKC. The purpose of this review is to summarize evidence on the pathogenic role of innate immunity, neuroimmune reaction, and hormonal changes in VKC. Increasing understanding of the pathogenic mechanisms behind VKC may lead to the identification of novel biomarkers for diagnosis and/or potential therapeutic targets in order to improve the management of this challenging condition.