Assessment of Corneal Alterations by Confocal Microscopy in Vernal Keratoconjunctivitis

The Role of In Vivo Confocal Microscopy in Ocular Allergies

In vivo confocal microscopy (IVCM) is a non-invasive imaging technique used to visualize the layers of the cornea and conjunctiva in real time. In patients with atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC), this technology can be useful in diagnosing and monitoring the disease, as well as evaluating the efficacy of treatments. IVCM can reveal subclinical abnormalities in the corneal and conjunctival epithelium such as inflammatory cell infiltrates and tissue damage, which can provide insight into the pathogenesis of AKC. In AKC, IVCM reveals changes around the conjunctival papillae, inflammatory cells around punctate defects in the corneal epithelium, changes in subbasal nerve morphology, and deteriorations in the goblet cells in the meibomian gland are observed. In VKC, alterations can be observed in the diameter, brightness and nucleus/cytoplasm ratio of the superficial epithelial cells in the cornea. The use of IVCM in AKC and VKC can therefore aid in the early detection and management of the disease, as well as contribute to a better understanding of its underlying mechanisms.

Examination of corneal microstructure in the quiescent phase of vernal keratoconjunctivitis using in vivo confocal microscopy

INTRODUCTION

This study investigated the morphological characteristics of corneal microstructure in the quiescent phase of vernal keratoconjunctivitis (VKC).

METHODS

Twenty patients with quiescent VKC and 25 healthy subjects were included. In vivo confocal microscopy (IVCM) of the central cornea was performed. Cellular density of each layer and the morphology of subbasal nerve plexus (SBNP) was analysed. Langerhans cell density (LCD), morphology (LCM), and field area (LCF) were also examined.

RESULTS

No differences were found either in cell densities nor in SBNP morphology (p > 0.05). LCD, LCM and LCF were significantly higher in the VKC group (p = 0.005, p < 0.001 and p < 0.001, respectively). The severity of papillary hypertrophy had a significant impact on LCD, LCM and LCF (β-coefficient: 19.541, p < 0.001; β-coefficient: 0.283, p < 0.001 and β-coefficient: 595.255, p < 0.001, respectively).

DISCUSSION

In quiescent VKC, LCD, LCM, and LCF were increased, and they were associated with the severity of papillary hypertrophy. Alterations of Langerhans cells indicate a subclinical inflammatory process without ocular 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.

Corneal and lens densitometry with Pentacam HR in children with vernal keratoconjunctivitis

CLINICAL RELEVANCE

Corneal and lens densitometry measurements provide clinically important information for the evaluation and monitoring of corneal and lens health in patients with vernal keratoconjunctivitis.

BACKGROUND

To compare the corneal and lens densitometry values between paediatric patients with vernal keratoconjunctivitis (VKC) and healthy individuals.

METHODS

This study included 72 eyes of 72 patients with VKC (25 with mild VKC [Group 1], 22 with moderate VKC [Group 2], and 25 with severe VKC [Group 3]), and 25 eyes of 25 healthy subjects (Group 4). Corneal and lens densitometry values were measured using Pentacam HR as follows: for corneal densitometry in two different corneal zones (0-2 and 2-6-mm) and four different corneal depths (at the total thickness, anterior, central, and posterior layers), and lens densitometry in three different lens zones (Zone 1: 2.0-mm, Zone 2: 4.0-mm, and Zone 3: 6.0-mm).

RESULTS

In the 0-2-mm corneal zone for the total thickness and all three layers, corneal densitometry values in Group 3 were significantly higher than those in Groups 1, 2, and 4 (for all values p < 0.012). There was no significant difference in the mean corneal densitometry values between Groups 1 and 2 (for all values p > 0.05). In these groups, the mean corneal densitometry values were significantly higher than those in Group 4 for the anterior layer in the 0-2 and 2-6-mm corneal zones (for all values p < 0.012). The mean values for Zone 3 and average lens densitometry values in Groups 2 and 3 were significantly higher than those in Group 4 (p = 0.001 and p = 0.001, respectively).

CONCLUSION

The current study showed corneal clarity changes in patients with mild, moderate, and especially severe VKC. An increase in the lens densitometry values was also observed in patients with moderate and severe VKC than in healthy individuals.

Eye drop emulsion containing 0.1% cyclosporin (1 mg/mL) for the treatment of severe vernal keratoconjunctivitis: an evidence-based review and place in therapy

Vernal keratoconjunctivitis (VKC) is a rare, recurrent and multifactorial ocular disease, which typically flares up during spring and affects especially male children and adolescents. This condition does not usually respond to common treatments with antihistamines or mast cells stabilizers, whereas corticosteroids have effective results. Corticosteroids need to be carefully administered, to avoid adverse effects, mainly the secondary development of glaucoma, cataracts, or infections. Immunosuppressive agents, such as cyclosporin (CyA) or tacrolimus are, therefore, frequently employed in VKC patients. Only the 0.1% CyA (1 mg/mL) concentration has an approved and specific clinical indication for the treatment of VKC and this drug was given the denomination of orphan drug by the European Commission (EU/3/06/360) in 2006. So far, few studies have been conducted to evaluate the efficacy and the side effects of topical 0.1% CyA. Different topical CyA concentrations, ranging from 0.05% to 2%, and various types of formulation are available at the moment. In the future, 0.1% CyA will presumably take an important part in the management of VKC. The present review focuses on eye drops containing 0.1% CyA; however, more studies will be needed to define its long-term efficacy in the natural course of this severe ocular disease.

Therapeutic effects of Houttuynia eye drops combined with olopatadine hydrochloride eye drops on vernal keratoconjunctivitis

Therapeutic effects and safety of houttuynia eye drops combined with olopatadine hydrochloride eye drops on vernal keratoconjunctivitis (VK) were evaluated. A total of 926 patients with VK were collected in the Eye Hospital of Wenzhou Medical University from July 2011 to January 2017. Patients were divided into group A, B and C according to the use of different eye drops. Group A included 276 patients who were treated with houttuynia eye drops; group B included 305 patients who were treated with olopatadine hydrochloride eye drops; group C included 345 patients who were treated with houttuynia eye drops and olopatadine hydrochloride eye drops. Treatment was performed for 14 days. Eye symptoms before and after treatment, and at 1 h, 7 days and 14 days after drug administration were compared among groups to evaluate the therapeutic effect. At 1 h after drug administration, highest excellent rate was observed in group C, followed by group A, and good outcome rate was significantly higher in group C than in the other two groups (P<0.05), and effective rate was also significantly higher in group C than in the other two groups (P<0.05). At 7 days after treatment, excellent rate was significantly higher in group C than in the other two groups (P<0.05), and effective rate was higher in group C than in group B (P<0.05). At 14 days after treatment, excellent rate was significantly higher in group C than in the other two groups (P<0.05), while lowest good outcome rate and ineffective rate were found in group C, and no significant differences were found between group A and B (P>0.05). Houttuynia ophthalmic solution and olopatadine hydrochloride eye drops can both achieve good effect in the treatment of VK, and combined use of them can increase the efficacy and shorten treatment period. So, the combined treatment should be popularized.

Tear Ferning Test and Pathological Effects on Ocular Surface before and after Topical Cyclosporine in Vernal Keratoconjunctivitis Patients

Background

Vernal keratoconjunctivitis (VKC) is a rare ocular surface inflammatory disease that affects mainly boys in the first decade of life. Clinical observations show that it generally regresses spontaneously with the onset of puberty, but therapeutic measures must be taken before then to control the course of the disease.

Purpose

To evaluate the role of the lacrimal mucous component in VKC patients and compare tear ferning test (TFT) modifications, MUC5AC levels in tears, and density of conjunctival goblet cells to clinical characteristics before and after treatment with cyclosporine A (CY) in eye drops.

Methods

Forty-seven patients affected by VKC and 30 healthy subjects aged between 3 and 16 years of life were enrolled. All individuals were submitted to complete eye examination and skin prick test (SPT) for the most common allergens. Then, they were subjected to collection of the tears and to impression cytology to evaluate TFT, MUC5AC levels, and conjunctival goblet cell density, before and after treatment with CY in eye drops.

Results

Comparing the VKC group vs. the control group at baseline, a significant alteration in the degree of the ferns was found, indicating a pathological condition of the lacrimal mucous layer. In addition, an increased number of goblet cells were observed in the patients. The concentration of lacrimal secretory mucins (MUC5AC) did not show significant differences between the 2 groups. Patients treated with CY have reported improvements of some signs and symptoms of disease activity, including TFT, and a tendency of conjunctival goblet cell density to normalise.

Conclusions

The results obtained demonstrated for the first time a significant alteration of the lacrimal mucin component evaluated in the VKC group, and an improvement of the latter after CY therapy.

Increased Lacrimal Fluid Level of HMGB1 in Vernal Keratoconjunctivitis

Purpose: The aim of the present prospective study was to evaluate the lacrimal fluid concentration of HMGB1 in young patients affected by Vernal Keratoconjunctivitis (VKC) compared to a control group of healthy subjects of same age. Methods: Tear fluids was collected in a group of VKC patients and compared to a control group of healthy subjects. HMGB1 concentration was measured using the HMGB1 ELISA II test both in VCK and control subjects. Results: The mean concentration of HMGB1 in tear fluids of 45 VKC patients was 0,977 ± 0,72 ng/ml whereas in the control group was 0,24 ± 0,25 ng/ml and the difference was statistically significant (p = 0,000106) Conclusion: The concentration of HMGB1 in VCK patients was found to be significantly increased, suggesting a possible role of this protein in the inflammatory mechanism of VKC.

Corneal backward scattering and higher-order aberrations in children with vernal keratoconjunctivitis and normal topography

PURPOSE

To investigate the corneal backward scattering and higher-order aberrations (HOAs) in children with vernal keratoconjunctivitis (VKC) and normal topography.

METHODS

Thirty-six eyes of 22 patients with VKC and 54 eyes of 34 normal subjects were included. All participants had clear cornea, absence of dry eyes and a normal corneal tomography. Scheimpflug imaging was used to measure corneal backward scattering in zones centred on the corneal apex (central 2-mm zone and paracentral 2- to 6-mm zone), and HOAs were compared between VKC and normal control.

RESULTS

The mean age of participants was 12.0 ± 4.1 years in VKC group and 11.2 ± 4.1 years in control group (p = 0.339). There was no significant intergroup difference in mean keratometry, astigmatism and apex pachymetry (p ≥ 0.076). Total corneal backscatter was higher in the VKC group compared to the control group (p ≤ 0.012). Anterior and posterior cornea displayed a higher level of backward scattering in the VKC group (p < 0.001 for anterior; p ≤ 0.048 for posterior). Patients with VKC exhibited higher total HOAs and coma (p ≤ 0.036). There were significant correlations between total anterior HOAs and backward scattering measured at the central (r = 0.500; p = 0.032) and paracentral zones (r = 0.470; p = 0.024) for VKC.

CONCLUSION

The current study showed optical quality changes in patients with clear corneas and quiescent VKC. An increase in corneal backward scattering and HOAs was noted in patients with VKC as compared to normal patients.

Analysis of the Pathogenic Factors and Management of Dry Eye in Ocular Surface Disorders

The tear film represents the interface between the eye and the environment. The alteration of the delicate balance that regulates the secretion and distribution of the tear film determines the dry eye (DE) syndrome. Despite having a multifactorial origin, the main risk factors are female gender and advanced age. Likewise, morphological changes in several glands and in the chemical composition of their secretions, such as proteins, mucins, lipidics, aqueous tears, and salinity, are highly relevant factors that maintain a steady ocular surface. Another key factor of recurrence and onset of the disease is the presence of local and/or systemic inflammation that involves the ocular surface. DE syndrome is one of the most commonly encountered diseases in clinical practice, and many other causes related to daily life and the increase in average life expectancy will contribute to its onset. This review will consider the disorders of the ocular surface that give rise to such a widespread pathology. At the end, the most recent therapeutic options for the management of DE will be briefly discussed according to the specific underlying pathology.

Dry Eye in Vernal Keratoconjunctivitis: A Cross-Sectional Comparative Study

The purpose of this comparative cross-sectional study was to investigate the use of standardized clinical tests for dry eye in pediatric patients with active and quiet vernal keratoconjunctivitis (VKC) and to compare them with healthy children.We recruited 35 active VKC, 35 inactive VKC, and 70 age-matched control healthy subjects. Each child underwent a complete eye examination, including visual analog scale symptoms assessment, biomicroscopy, fluorescein break-up time (BUT), corneal fluorescein and conjunctival lissamine green staining, corneal esthesiometry, Schirmer test with anesthetic, and meibomian glands inspection and expression.Active VKC patients showed significantly increased symptoms and signs of ocular surface disease, compared with the other 2 groups. Inactive VKC patients, compared with control subjects, showed increased photophobia (P < 0.05; Mann-Whitney U test), conjunctival lissamine green staining and Schirmer test values, and reduced BUT and corneal sensitivity [P < 0.05 by analysis of variance (ANOVA) least significant difference posthoc test for BUT and Schirmer; P < 0.001 by Mann-Whitney U test for lissamine green staining and corneal sensitivity].Our results confirm the association between VKC and short-BUT dry eye. This syndrome seems to affect the ocular surface in quiescent phases too, determining abnormalities in tear film stability, epithelial cells integrity, and corneal nerves function. The very long-term consequences of this perennial mechanism of ocular surface damage have not been fully understood yet.