Tear Film Lipid Layer Alterations in Allergic Conjunctivitis

Effects of common eye diseases in children and their treatment measures on ocular surface homeostasis: A review

Ocular surface homeostasis plays a vital role in maintaining of eye health. Dry eye disease is one of the prominent and typical manifestations of disruption of ocular surface homeostasis that leads to the worsening of ocular surface homeostasis that leads to the worsening of ocular surface disease when it interacts with other pathogenic factors. However, disruption in ocular surface homeostasis in children is often overlooked because of the current methods of assessing ocular surface homeostasis. This review summarizes the main factors affecting ocular surface homeostasis in children, with the aim of drawing the attention of clinicians to the disruption of ocular surface homeostasis in children when dealing with such diseases. Ocular surface homeostasis involves several interrelated components, each of which plays a nonnegligible role in ocular surface homeostasis. Unlike adults, children have a stronger lacrimal gland secretion capacity and milder symptoms when there is a slight disruption of the ocular surface homeostasis. In addition, children's expressive abilities were weaker. Therefore, dry eye in children is often ignored by doctors and parents, and clinicians should pay more attention to the protection of ocular surface homeostasis when treating children with these diseases. Therefore, there is a need for diagnostic criteria for dry eye disease specific to children.

Novel Application of Immunochromatographic Assay for Measurement of Total Tear Immunoglobulin E

PURPOSE

The aim of this study was to evaluate the efficacy of a new immunochromatographic assay (Aifeice) in the diagnosis of allergic conjunctivitis diseases (ACDs) and to explore the relationship between Aifeice testing results and the severity of ACDs.

METHODS

A multicenter prospective cross-sectional study (390 patients diagnosed with ACDs and 619 healthy controls) was conducted. Patients with ACDs were scored based on clinical symptoms. All participants received the Aifeice test. The positive testing results were further divided into 3 immunoglobulin E (IgE) grades. Statistical analysis was performed to evaluate the indexes associated with the testing results.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and total coincidence rate of the Aifeice test were 96.15%, 98.87%, 98.17%, 97.61%, and 97.82%, respectively. The total clinical score was significantly correlated with the IgE grade. The factors that affected the IgE score were conjunctival hyperemia, conjunctival swelling, conjunctival papillae, and Horner-Trantas dots.

CONCLUSIONS

The high sensitivity and specificity of Aifeice in the diagnosis of ACD was confirmed. This new immunochromatographic assay could be used to assess the severity of ACD.

Symptomatic Dry Eye Disease and Associated Factors Among Adult Diabetic Patients in Adare General Hospital, Hawassa City, Southern Ethiopia, 2023

Introduction

Symptomatic dry eye disease is a multifactorial ocular surface condition caused by disruption of the precorneal tear film and is a common clinical finding in diabetic patients. However, there was no study on the prevalence and associated factors of symptomatic dry eye disease among diabetic patients in Ethiopia or in the study area.

Purpose

This study aimed to investigate the prevalence and associated factors of symptomatic dry eye disease among adult diabetic patients in Adare General Hospital, Hawassa City, Southern Ethiopia, in 2023.

Methods

A hospital-based cross-sectional study design was conducted on 493 adult diabetic patients who were selected using systematic random sampling, from April 23 to June 8, 2023. Data were collected through a face-to-face interview using an ocular surface disease index questionnaire. Binary logistic regression was performed to identify factors potentially associated with symptomatic dry eye disease. Variable with a P value of <0.05 was considered statistically significant.

Results

A total of 488 subjects participated in this study with a response rate of 99%. The prevalence of symptomatic dry eye disease was 34.8% (95% CI = 30.6-39.1). College and university educational status (AOR = 5.88, 95% CI = 2.25-15.38), government employed (AOR = 2.22, 95% CI = 1.05-4.68), use of visual display unit >5 hours (AOR = 4.41, 95% CI = 1.51-12.87), duration of diabetes ≥11 years (AOR = 3.57, 95% CI = 1.28-9.90), poor glycemic control (AOR = 2.13, 95% CI = 1.21-3.75), allergic conjunctivitis (AOR = 1.99, 95% CI = 1.12-3.54), and debris in the tear film (AOR = 3.63, 95% CI = 1.53-8.61) were positively associated with symptomatic dry eye disease.

Conclusion

The study revealed a high prevalence of symptomatic dry eye disease. Higher educational status, government employed, use of visual display unit, longer duration of diabetes, poor glycemic control, allergic conjunctivitis, and tear film debris were significantly associated with symptomatic dry eye disease. Breaks in screen use, good glycemic control, and treatment of ocular morbidities such as allergic conjunctivitis and debris in the tear film were recommended for all diabetic patients.

Using the AllerSearch Smartphone App to Assess the Association Between Dry Eye and Hay Fever: mHealth-Based Cross-Sectional Study

BACKGROUND

Dry eye (DE) and hay fever (HF) show synergistic exacerbation of each other's pathology through inflammatory pathways.

OBJECTIVE

This study aimed to investigate the association between DE and HF comorbidity and the related risk factors.

METHODS

A cross-sectional observational study was conducted using crowdsourced multidimensional data from individuals who downloaded the AllerSearch smartphone app in Japan between February 2018 and May 2020. AllerSearch collected the demographics, medical history, lifestyle and residential information, HF status, DE symptoms, and HF-related quality of life. HF symptoms were evaluated using the nasal symptom score (0-15 points) and nonnasal symptom score (0-12 points). HF was defined by the participants' responses to the questionnaire as HF, non-HF, or unknown. Symptomatic DE was defined as an Ocular Surface Disease Index total score (0-100 points), with a threshold score of 13 points. HF-related quality of life was assessed using the Japanese Allergic Conjunctival Disease Standard Quality of Life Questionnaire (0-68 points). We conducted a multivariable linear regression analysis to examine the association between the severity of DE and HF symptoms. We subsequently conducted a multivariable logistic regression analysis to identify the factors associated with symptomatic DE (vs nonsymptomatic DE) among individuals with HF. Dimension reduction via Uniform Manifold Approximation and Projection stratified the comorbid DE and HF symptoms. The symptom profiles in each cluster were identified using hierarchical heat maps.

RESULTS

This study included 11,284 participants, classified into experiencing HF (9041 participants), non-HF (720 participants), and unknown (1523 participants) groups. The prevalence of symptomatic DE among individuals with HF was 49.99% (4429/9041). Severe DE symptoms were significantly associated with severe HF symptoms: coefficient 1.33 (95% CI 1.10-1.57; P<.001) for mild DE, coefficient 2.16 (95% CI 1.84-2.48; P<.001) for moderate DE, and coefficient 3.80 (95% CI 3.50-4.11; P<.001) for severe DE. The risk factors for comorbid symptomatic DE among individuals with HF were identified as female sex; lower BMI; medicated hypertension; history of hematologic, collagen, heart, liver, respiratory, or atopic disease; tomato allergy; current and previous mental illness; pet ownership; living room and bedrooms furnished with materials other than hardwood, carpet, tatami, and vinyl; discontinuation of contact lens use during the HF season; current contact lens use; smoking habits; and sleep duration of <6 hours per day. Uniform Manifold Approximation and Projection stratified the heterogeneous comorbid DE and HF symptoms into 14 clusters. In the hierarchical heat map, cluster 9 was comorbid with the most severe HF and DE symptoms, and cluster 1 showed severe HF symptoms with minimal DE-related symptoms.

CONCLUSIONS

This crowdsourced study suggested a significant association between severe DE and HF symptoms. Detecting DE among individuals with HF could allow effective prevention and interventions through concurrent treatment for ocular surface management along with HF treatment.

How Can We Best Diagnose Severity Levels of Dry Eye Disease: Current Perspectives

Dry eye disease (DED) is a common ocular condition, but the diagnosis relative to other ocular conditions and the evaluation of severity of the condition has often been difficult. This challenge can be due to clinical signs and symptoms not always correlating with each other. An understanding of the various components which create the condition, as well as the diagnostic measures used to evaluate these components, is useful to the clinician working with DED patients. This review paper will discuss traditional diagnostic options, diagnostic imaging, and Advanced Point of Care testing capabilities to determine the severity level of dry eye disease more adequately.

Ocular surface characteristics in pediatric vernal keratoconjunctivitis: a clinico-cytological study

PURPOSE

To compare the ocular surface parameters of children with vernal keratoconjunctivitis (VKC) with those of healthy controls and to correlate cytological characteristics with clinical findings and disease severity.

METHODS

Newly diagnosed cases of VKC, not currently being treated, were recruited, along with age-matched controls with no ocular comorbidities. The Ocular Surface Disease Index questionnaire (OSDI) was administered to all children. Slit lamp biomicroscopy for meibomian gland dysfunction and ocular surface analysis was performed, including tear meniscus height, noninvasive tear film break-up time, lipid layer thickness, meibomian gland morphology, and meibomian gland duct distortion on meibography imaging. Conjunctival impression cytology was also performed.

RESULTS

A total of 68 VKC patients and 33 controls were included. Statistically significant difference was seen in the mean OSDI score (30 ± 13.7 vs 16.1 ± 3 [P ≤ 0.01]), lipid layer thickness (24.2 ± 7.9 nm vs 69.9 ± 15.1 nm [P <0.001]), and noninvasive tear film break-up time (6.8 ± 1.7 vs 12.5 ± 1.8 sec [P < 0.01]) between groups. Mean tear meniscus height was 0.22 ± 0.06 mm in the VKC and 0.24 ± 0.04 mm in the control group (P = 0.096). Significant association was seen between grade of squamous metaplasia and severity of VKC (P < 0.01). Severity of VKC was found to be positively correlated with OSDI score (r = 0.767), grade of squamous metaplasia (r = 0.64) and negatively correlated with noninvasive tear film break-up time (r = -0.468), and lipid layer thickness (r = -0.253).

CONCLUSIONS

This study highlights the poor ocular surface health of children with VKC, with severe disease being associated with worse forms of dry eye disease.

Symptomatic dry eye disease and associated factors among postgraduate students in Ethiopia

Background

Symptomatic dry eye disease is a growing public health challenge especially among those who are visual display unit (VDU) users and other long-time near activity workers. Globally, computer user adults experience a surge in the prevalence of dry eye. Data is insufficient on the prevalence of dry eye disease among postgraduate students in Ethiopia. Therefore, the present was aimed to assess the prevalence of dry eye and its associated factors among postgraduate students at the University of Gondar, Northwest Ethiopia.

Methods

A cross-sectional study was conducted on a total of 423 postgraduate students who were selected based on a simple random sampling technique. Data was collected through online symptom-based ocular surface disease index questionnaire. Binary logistic regression was used to test the association and p-value of <0.05 was considered to determine the significance of the association.

Results

From the total postgraduate students, 404 completed the study with a response rate of 95.5%. The prevalence of symptomatic dry eye disease was 50.5% (95% CI, 45.1%-54.9%). Average continuous visual display unit use for 2-4hours per day[AOR = 2.57 (95% CI, 1.27–5.21)] and for> 4hours per day[AOR = 3.77 (95% CI 1.87–7.59)], duration of visual display unit use for 3–5 years [AOR = 2.24 (95% CI, 1.17–4.31)], 6–8 years [AOR = 2.46 (95% CI,1.31–4.62)] and > 8 years [AOR = 3.25 (95% CI, 1.63–6.48)], average sleeping hour < 7 hours/day within last week [AOR = 2.17 (95% CI, 1.35–3.49)] and current known allergic conjunctivitis [AOR = 5.42 (95% CI, 2.43–12.10)] were significantly associated with symptomatic dry eye disease.

Conclusion and recommendation

In this study, about half of postgraduate students faced symptomatic dry eye disease. Significant association was observed between symptomatic dry eye disease and average continuous hours of visual display unit use, duration of visual display unit use in years, shortage of sleep and current known allergic conjunctivitis. It is advisable for postgraduate students to limit screen exposure hour and establish regular breaking time along their exposure. It is also advisable to have optimum sleep as possible. It is also important to explore dry eye disease on a large sample incorporating clinical tests.

Prevalence of Comorbidity between Dry Eye and Allergic Conjunctivitis: A Systematic Review and Meta-Analysis

This systematic review aimed to determine the comorbid dry eye (DE) and allergic conjunctivitis (AC) prevalence. We searched PubMed and EMBASE for articles published until 22 March 2022, combining the terms “(dry eye OR keratoconjunctivitis sicca) AND allergic conjunctivitis.” Study-specific estimates (DE and AC incidence rates among patients with AC and DE, respectively) were combined using the one-group meta-analysis in a random-effects model. The initial search yielded 700 studies. Five articles reporting AC incidence among individuals with DE and six articles reporting DE incidence among individuals with AC were included in the qualitative synthesis. In these nine articles, the total sample size was 7254 patients. The DE incidence among individuals with AC was 0.9–97.5%; the AC incidence among individuals with DE was 6.2–38.0%. One-group meta-analysis using a random-effects model showed that 47.2% (95% confidence interval: 0.165–0.779; 320/1932 cases) of patients with AC had comorbid DE and 17.8% (95% confidence interval: 0.120–0.236; 793/4855 cases) of patients with DE had comorbid AC, as defined by each article. Complimentary screening and treatment for patients with DE and AC may improve long-term outcomes and prevent chronic ocular damage in highly susceptible populations.

Aqueous-Deficient Dry Eye Exacerbates Signs and Symptoms of Allergic Conjunctivitis in Mice

Dry eye disease (DED) and allergic conjunctivitis affect a large number of patients, and many patients usually have both symptoms. We investigated the interactions between DED and allergic conjunctivitis in mice. Four experimental groups were compared: control, DED, allergy, and allergy with DED. DED was induced by removing the extraorbital lacrimal glands of the mice. Allergic conjunctivitis was induced by intraperitoneal administration of ovalbumin and antigen eye drops. The early phase reaction of the allergy was evaluated using the clinical score, scratching behavior, and vascular permeability in the conjunctiva. Epithelial barrier function was assessed by an LC-biotin assay. Tear fluid volume and corneal fluorescein staining decreased in the DED and allergy with DED groups. LC-biotin penetrated the entire epithelium of both the cornea and conjunctiva in DED mice. The clinical score of the early phase reaction was higher in allergy-induced mice than in non-allergy mice. Edema of the eyelid and conjunctiva were aggravated in mice with DED. The number of scratching episodes and leakage of Evans blue into the conjunctiva were higher in allergy-induced DED mice than in control mice. The presence of aqueous-deficient dry eye caused ocular surface epithelial damage and exacerbated allergic signs and symptoms.

Characterization of the thickness of the Tear Film Lipid Layer in Meibomian Gland Dysfunction using high resolution optical microscopy

PURPOSE

To evaluate the thickness of the tear film lipid layer (TFLL) in meibomian gland dysfunction (MGD) using a high-resolution optical microscope.

METHODS

The Ocular Surface Disease Index (OSDI) and meibum grade score (MGS) were used to classify 190 subjects into four groups: normal (OSDI<13 and MGS<10), mixed (OSDI≥13 and MGS<10), asymptomatic MGD (OSDI<13 and MGS≥10), and MGD (OSDI≥13 and MGS≥10). The high-resolution optical microscope was used to capture TFLL images in vivo. The histograms of TFLL thickness were analyzed and curve-fitted using probability density functions (PDFs).

RESULTS

There were three obvious peaks in the distributions of TFLL across the groups. From the curve-fitting process, the main outcomes are displayed according to each Gaussian function with the position of peak (μ) and the summed percentage within the range of standard deviation (σ). The normal group had distribution as follows: 33.3 ± 0.005 nm, 26%; 53.9 ± 0.019 nm, 40%; 79.4 ± 0.064 nm, 12%. The mixed group had a distribution as follows: 33.8 ± 0.004 nm, 32%; 53.1 ± 0.115 nm, 21%; 71.7 ± 0.232 nm, 27%. The asymptomatic MGD group had a distribution as follows: 33.5 ± 0.004 nm, 20%; 49.2 ± 0.041 nm, 25%; 62.9 ± 0.063 nm, 47%. The MGD group had a distribution as follows: 34.3 ± 0.004 nm, 34%; 53.7 ± 0.022 nm, 28%; 74.9 ± 0.060 nm, 16%.

CONCLUSIONS

The MGD and mixed groups had the largest percentages of TFLL thicknesses fall within the thinnest modes (peak 34.3 and 33.8 nm, respectively). These data show that measures of central tendency (e.g., averages, medians) do not fully appreciate the variable distributions of TFLL across disease spectra.

Beyond dry eye: how co-morbidities influence disease phenotype in dry eye disease

Dry Eye Disease (DED) is a complex and multifactorial disorder of tear homoeostasis that results in pain, visual disturbance, and ocular surface damage. It is highly prevalent around the world and is associated with many co-morbidities that may contribute to or exacerbate symptoms and signs of disease and affect disease phenotype. However, DED is not one disease and can manifest with a variety of symptoms and/or signs. In this review, we discuss relationships between various co-morbidities and DED phenotypes. For example, individuals with immune mediated diseases, like Sjögren's Syndrome and Graft versus Host Disease, often present with aqueous tear deficiency (ADDE) in the setting of lacrimal gland dysfunction. Individuals with disorders that affect the periocular skin, like rosacea and seborrhoeic dermatitis, often present with evaporative dry eye (EDE) in the setting of eyelid and/or meibomian gland abnormalities. Individuals with pain related disorders, such as chronic pain syndrome and migraine, often present with ocular pain out of proportion to tear film abnormalities, often with accompanying corneal nerve hypersensitivity. Individuals with diabetes mellitus often present with an epitheliopathy in the setting of decreased sensation (neurotrophic keratitis). While not absolute, understanding relationships between co-morbidities and DED phenotypes can help tailor a therapeutic plan to the individual patient.

Raman spectroscopy may allow rapid noninvasive screening of keratitis and conjunctivitis

Keratitis and conjunctivitis are the most common ocular diseases, their symptoms are similar and easy to confuse, however infectious conjunctivitis is highly contagious. If misdiagnosed, it may worsen the disease and pose a threat to public health.This is a preclinical study to propose a method for rapid and accurate screening of keratitis and conjunctivitis by combining tear Raman spectroscopy with deep learning models that may be applied to clinical applications in the future.The tears of 16 cases of keratitis patients, 13 cases of conjunctivitis patients and 46 cases of healthy subjects were collected, and their Raman spectra were compared and analyzed. By adding different decibels of Gaussian white noise to expand the data, the performance of the tear Raman spectra with a large sample size in the deep learning model was discussed. Principal component analysis (PCA), partial least squares (PLS) and maximum correlation minimum redundancy (mRMR) were used for feature extraction. The processed data were imported into convolutional neural network (CNN) and recurrent neural network (RNN) depth models for classification. After the data were enhanced and processed by PLS, the highest classification accuracy of healthy subjects and keratitis patients, healthy subjects and conjunctivitis patients, and keratitis and conjunctivitis patients reached 94.8%, 95.4%, and 92.7%, respectively. The results of this study show that the use of large sample tear Raman spectra data combined with PLS feature extraction and depth learning algorithms may have great potential in clinical screening of keratitis and conjunctivitis.

Allergie und Trockenes Auge

Allergische Erkrankungen der Augenoberfläche (okuläre Allergie, OA) und Trockene Augen (Keratokonjunktivitis sicca, KCS) sind zwei häufige klinische Entitäten, die oft konkomitant auftreten und sich vice versa gegenseitig bedingen. Dieser Artikel fasst die Assoziationen zwischen OA und KCS in Pathophysiologie, Diagnostik und Therapie zusammen und wird aufzeigen, dass das Kardinalsymptom des Juckreizes kein allgemeingültiges Dogma darstellen muss, anhand dessen diese 2 Entitäten korrekt voneinander differenziert werden können. Es folgt weiters ein Überblick über Überempfindlichkeits-Reaktionen der Augenoberfläche, welche sich häufig als KCS äußern, sowie über KCS als okuläre Nebenwirkung von systemischen anti-allergischen Medikamenten.

Quantitative evaluation of lipid layer thickness and blinking in children with allergic conjunctivitis

Purpose

To quantitatively evaluate the lipid layer thickness (LLT) and blinking in children with or without allergic conjunctivitis (AC), and to compare those between the different types of AC.

Methods

For this case–control study, 81 children with symptomatic AC with an average age of 9.62 ± 2.67 years were enrolled and subdivided according to the subtypes of AC, including seasonal/perennial allergic conjunctivitis group and vernal keratoconjunctivitis (VKC)/atopic keratoconjunctivitis (AKC) group. Another 82 age-matched healthy children were enrolled as control group. All subjects underwent routine eye examination and measurements of LLT, the number of incomplete or total blinking, partial blinking rate by the LipiView interferometer over a 10-s period. Other ocular surface assessment included fluorescein tear breakup time (TBUT), lower tear meniscus height, meibomian gland loss (MGL), meibum expressibility and quality.

Results

Pediatric patients with AC had significant thinner LLT, shorter TBUT, decreased total blinking but increased partial blinking rate, especially in those with VKC/AKC (all P < 0.05). A significant deterioration of meibomian gland parameters was observed in AC group when compared with control subjects, demonstrated by severe upper and lower MGL, lid margin abnormalities, decreased meibum expressibility, and abnormal meibum quality, all of which were worse in the severe type of AC (all P < 0.05). Thinner LLT was significantly correlated with decreased TBUT (β = 3.666, P < 0.001) and severity of upper MGL (β =  − 7.701, P = 0.002).

Conclusion

Decreased LLT and blinking disorders in pediatric patients with AC may contribute to lipid layer deficiency in the long run, which should be considered and appropriately diagnosed for a more precise treatment.

Allergy and Dry Eye Disease

Ocular allergy (OA) and dry eye disease (DED) are the most common ocular surface disorders with a potential severe impact on the patient's quality of life. OA and DED may coexist and have a significant clinical overlap. Therefore, clinical features commonly believed to be distinctive of OA or DED may be sometimes insufficient for a differential diagnosis. Alterations of the tear film, epithelial barrier, and corneal innervation are described in OA and can pave the way to DED. Conversely, DED may facilitate or worsen allergic reactions in predisposed (atopic) patients. For these reasons, OA and DED should be considered as reciprocal predisposing conditions that share ocular surface inflammation as a common background.

Changes in meibum composition following plaque bachytherapy for choroidal melanoma

Objectives

Dry eye is common when external beam radiation is used for the treatment of choroidal melanoma (CM). As meibum structure and composition have been related to dry eye, we determined if plaque bachytherapy for CM alters meibum composition.

Design

¹H-NMR spectroscopy was used to measure the lipid composition of meibum.

Setting

The University of Louisville, Kentucky, USA.

Participants

All 13 participants had CM and one participant had iris melanoma.

Main outcome measures

Cholesteryl ester (CE) to wax ester (WE) ratio, amount of meibum esters (ME) and meibum lipid saturation were measured.

Results

ME decreased by 80%±18% (±99% CI) in 11 eyes that were treated compared with the contralateral untreated eye. ME increased by 181% in two eyes that were treated compared with the contralateral untreated eye. The mole % CE/WE for meibum was significantly (p<0.0001) 67% lower in eyes that were irradiated compared with control eyes from donors without CM and were not treated. Plaque brachytherapy induced the de-esterification of CE. The intensity of the meibum cis double bond resonances did not change significantly (p>0.05).

Conclusion

Eyes that had plaque brachytherapy had a lower amount of expressible meibum and a lower CE/WE ratio compared with meibum from the contralateral eye that received no treatment and eyes that did not have uveal melanoma. Both the quality and quantity of meibum should be considered in designing a therapy for dry eye after plaque brachytherapy.

Evaluation of Lacrimal Drainage Function in the Anophthalmic Socket by Dacryoscintigraphy

PURPOSE

To investigate whether impaired lacrimal pump function is a possible cause of discharge in patients wearing an artificial eye compared with the remaining healthy eye.

METHODS

Consecutive patients wearing unilateral ocular prosthesis for ≥6 months were included in this retrospective study. Excluded were any deformities of eyelids or nasal passage, socket complications such as entropion, ectropion, ptosis, infection, pyogenic granuloma, contracted socket, obstruction of nasolacrimal duct diagnosed with lacrimal irrigation and a difference greater than 2 mm in terms of protrusion between two eyes detected by Hertel exophthalmometry. Patients were asked to score the levels of tearing and mucopurulent discharge between 0 and 5 to assess lacrimal drainage function subjectively. Furthermore, dacryoscintigraphy was performed to assess the functional status of the lacrimal system objectively.

RESULTS

Included were 32 subjects (12 females, 20 males; aged 32.94 ± 17.62, range 13-78). Mean duration of prosthetic wearing 26.41 ± 21.30 (6-72) months. The mean subjective scores of tearing and mucopurulent discharge were 1.56 ± 1.67 and 1.94 ± 1.63, respectively. The rate of functional stenosis was significantly higher in the anophthalmic socket side as compared to the healthy side (P = 0.002). The rates of a presac, preduct, and intraduct obstruction was notes as n = 9, n = 10, n = 1 and n = 0, n = 6, n = 2 in the anophthalmic side and the companion eye, respectively (P = 0.021).

CONCLUSION

Compared to paired healthy eyes, the ocular prosthesis exhibited significantly higher rates of functional lacrimal duct obstruction, especially at the presac level. The alterations in orbital volume and tear film composition in addition to reduced corneal reflex blinking may lead to the failure of lacrimal pump function in artificial eyes.

Novel Approaches for Imaging-Based Diagnosis of Ocular Surface Disease

Imaging has become indispensable in the diagnosis and management of diseases in the posterior part of the eye. In recent years, imaging techniques for the anterior segment are also gaining importance and are nowadays routinely used in clinical practice. Ocular surface disease is often synonymous with dry eye disease, but also refers to other conditions of the ocular surface, such as Meibomian gland dysfunction or keratitis and conjunctivitis with different underlying causes, i.e., allergies or infections. Therefore, correct differential diagnosis and treatment of ocular surface diseases is crucial, for which imaging can be a helpful tool. A variety of imaging techniques have been introduced to study the ocular surface, such as anterior segment optical coherence tomography, in vivo confocal microscopy, or non-contact meibography. The present review provides an overview on how these techniques can be used in the diagnosis and management of ocular surface disease and compares them to clinical standard methods such as slit lamp examination or staining of the cornea or conjunctiva. Although being more cost-intensive in the short term, in the long term, the use of ocular imaging can lead to more individualized diagnoses and treatment decisions, which in turn are beneficial for affected patients as well as for the healthcare system. In addition, imaging is more objective and provides good documentation, leading to an improvement in patient follow-up and education.

Effects of Oral Antihistamines on Tear Volume, Tear Stability, and Intraocular Pressure

The goal of this study was to investigate the effects of two commonly used oral antihistamines—diphenhydramine and loratadine—on tear volume, tear breakup time, and intraocular pressure. Placebo, diphenhydramine, and loratadine were administered for one week to 33 subjects experimentally blind to the treatment given. All the subjects received all three treatments over a period of six weeks. The outcome measures were the change in phenol red thread test (PRT), the tear breakup time (TBUT), and the intraocular pressure (IOP) of both eyes evaluated by experimentally masked observers. Neither of the mean changes in TBUT or IOP depended on the treatment given, but there was a significant monocular decrease in tear volume from diphenhydramine use. While we used an adequate treatment washout period of seven days, our investigation was limited by the short treatment times and inclusion of only young healthy patients. Overall, however, these results suggest that systemic diphenhydramine use should be limited to increase the effectiveness of conventional therapies. Clinicians should have fewer reservations about recommending the use of loratadine concurrent with dry eye treatments.

Topical Estrogen Therapy for Hyperopia Correction in Vivo

Purpose

In vitro studies found that 17β-estradiol (estrogen) modulates corneal biomechanical properties and reduces tissue stiffness. Therefore we hypothesized that topical estrogen might affect the refractive properties of the cornea, inducing a myopic shift.

Methods

Twelve female New Zealand white rabbits 16 weeks old were used. The rabbits were randomly divided to either the treatment group receiving 1.5% (w/v) estrogen eye drops or a control group receiving vehicle only (n = 6 each group). Both groups were given drops (50 µL) to the right eye every 12 hours for 35 days. Ocular examination, pachymetry, intraocular pressure (IOP), keratometry, and refraction were evaluated at baseline and on a weekly basis.

Results

No significant differences were observed between the two groups at baseline in all outcome measures. Both groups displayed corneal flattening and a hyperopic shift. However, the change rate was slower in the treatment group. Repeated measurements analysis revealed a statistically significant difference in keratometry readings between groups (P = 0.034) with steeper keratometry by up to 0.6 diopters in the treatment group. The difference between the two groups diminished and became statistically insignificant after treatment cessation. No significant changes were observed in IOP and pachymetry throughout the study period. No side effects were observed in either group.

Conclusions

Estrogen eye drops induced a myopic shift in keratometry readings. These results suggest that corneal refractive power might be manipulated pharmacologically. Further studies on the physiology behind this change are warranted to facilitate a pathway for development of novel pharmacologic treatments to correct refractive errors.

A Murine Model of Acute Allergic Conjunctivitis Induced by Continuous Exposure to Particulate Matter 2.5

Purpose

Several pieces of epidemiologic evidence have indicated PM2.5 (particulate matter with a diameter of 2.5 μm or less) as a causing factor of allergic conjunctivitis, but without experimental elucidation of mechanism. In the present study, PM2.5 in solution was directly applied to the mouse ocular surface to elucidate whether PM2.5 might cause allergic conjunctivitis, and its underlying mechanisms were analyzed.

Methods

ICR mice were challenged for 18 consecutive days with eye drops containing PM2.5 at 3.2, 6.4, and 12.8 mg/mL in 0.9% NaCl saline, along with the controls prepared in parallel without PM2.5 and another control group treated with both PM2.5 at 12.8 mg/mL and artificial tears. On day 19, the whole eyes and meibomian glands were harvested for histopathological analyses and assessment of clinical scoring, tear volume, tear breakup time, and tear ferning. Furthermore, goblet cells by periodic acid Schiff stain and infiltrated eosinophils by Giemsa stain were quantified and compared among study groups.

Results

Clinical scoring showed more eyelid edema, tearing, and scratching behaviors, with longer tear breakup time under the influence of increased PM2.5 concentrations. Tear ferning assay showed less tear crystal formation and decreased crystal branches after exposure to PM2.5. In addition, higher goblet cell density in the upper palpebral conjunctiva and extensive eosinophil infiltration in the entire conjunctiva and in the meibomian glands were induced by PM2.5.

Conclusions

These results demonstrate that PM2.5 can induce symptoms similar to clinical allergic conjunctivitis and that the murine acute allergic conjunctivitis model can be induced by direct exposure to PM2.5.

Ocular allergy as a risk factor for dry eye in adults and children

PURPOSE OF REVIEW

To provide an overview of the pathogenic mechanisms underlying the correlation between ocular allergy and dry eye disease (DED), highlighting how the first condition may be a risk factor for the second one.

RECENT FINDINGS

Recent advances in our comprehension of the pathogenesis of ocular allergy and DED allow identifying several pathways of interaction between these two conditions. A growing body of evidence supports the role of ocular allergy as a risk factor for DED. Ocular allergy, particularly the severe forms of keratoconjunctivitis, can impact on different key mechanisms of the DED vicious cycle, including tear film instability, ocular surface inflammation and damage, and neurosensory abnormalities.

SUMMARY

Ocular allergy and DED are two common, relevant, symptomatic, not mutually exclusive conditions affecting the ocular surface. They share some clinical and biochemical features. To better understand the complex interactions between these two conditions, it's essential to consider the very wide spectrum of clinical conditions included in the term ocular allergy and the still largely unexplored peculiarities of the pediatric ocular surface physio-pathology and DED.

An imaging system integrating optical coherence tomography and interferometry for in vivo measurement of the thickness and dynamics of the tear film

BACKGROUND

The outermost layer of the tear film consists of a thin lipid layer (LL). The lipid layer serves as a barrier against evaporation of the aqueous component of the tear film. The ability to simultaneously image both the lipid layer thickness and overall tear film thickness is novel, and will help further understandings of mechanisms of how the lipid layer assembles and interacts with the full tear film thickness.

METHODS

We developed a system that combines simultaneous optical coherence tomography (OCT) and thickness dependent fringes (TDF) interferometry for in vivo imaging of the tear film. The OCT possesses an axial resolution of 1.38 µm in tear film, providing an accurate measurement of the thickness of the overall tear film. The TDF can detect a minimal change of approximately 15 nm in LL thickness. In addition, the spatial resolution of TDF images in x-y plane is 5 µm.

RESULTS

The effect of instilling artificial tears on the PCTF and PLTF was examined. In both contact lens and non-contact lens wear, it could be observed from the OCT results that instillation of artificial tears increased the thickness of the overall tear film immediately, followed by a gradual reduction thereafter. These findings were consistent with other studies. However, unlike those previous reports, the thickness of the LL in this study was quantified simultaneously with the TDF subsystem. The results showed that bulking agents such as these artificial tears were not necessarily intended to increase the LL thickness. Immediately after instillation of artificial tears, the PCTF increased from 4.4 ± 0.97 to 20.3 ± 3.6 µm. The PCTF then decreased to 8.8 ± 2.1 µm at 4 min post-instillation. The thicknesses of the LL were 62.4 ± 14.5 nm, 48.7 ± 5.3 nm, and 55.2 ± 9.8 nm at pre-drop instillation, post-drop instillation, and 4-min post-drop instillation, respectively.

CONCLUSIONS

In this work, we have described a novel imaging system that integrated OCT and TDF imaging techniques, which may facilitate the study of many physiological and clinical aspects of the tear film.

Diagnostic tools in ocular allergy

Ocular allergy (OA) includes a group of common and less frequent hypersensitivity disorders frequently misdiagnosed and not properly managed. The diagnosis of OA is usually based on clinical history and signs and symptoms, with the support of in vivo and in vitro tests when identification of the specific allergen is required. To date, no specific test is available for the diagnosis of the whole spectrum of the different forms of OA. The lack of recommendations on diagnosis of OA is considered a medical need not only for allergists but also for ophthalmologists. This position paper aims to provide a comprehensive overview of the currently available tools for diagnosing OA to promote a common nomenclature and procedures to be used by different specialists. Questionnaires, sign and symptom grading scales, tests, and potential biomarkers for OA are reviewed. We also identified several unmet needs in the diagnostic tools to generate interest, increase understanding, and inspire further investigations. Tools, recommendations, and algorithms for the diagnosis of OA are proposed for use by both allergists and ophthalmologists. Several unmet needs in the diagnostic tools should be further improved by specific clinical research in OA.

High incidence of dry eye in young children with allergic conjunctivitis in Southwest China

PURPOSE

To identify the prevalence of dry eye in pediatric population with allergic conjunctivitis in Southwest China.

METHODS

A single-centre, prospective, case-control study conducted between May 2015 and December 2015 included 40 children, 3-6 years of age, with seasonal allergic conjunctivitis (SAC) or perennial allergic conjunctivitis (PAC) and 40 age- and gender-matched children undergoing medical healthy examination without history of allergy or dry eye as a control. A dry eye score system (DESS) was administered to both groups. Slit-lamp examinations including tear film break-up time (TFBUT) and fluorescent corneal staining (FCS) were performed. Correlation analyses were performed to evaluate associations between measures of dry eye and signs and symptoms of AC.

RESULTS

The prevalence of dry eye was 97.5% (78/80 eyes) in cases and 27.50% (22/80 eyes) in controls. Mean DESS score was 4.75 ± 2.22 in the case group and 0.80 ± 1.22 in the control group (p < 0.001). Symptoms of dry eye in the case group were mild (<6). Mean tear film break-up time was 6.54 ± 1.48 seconds in the case group and 10.04 ± 1.79 seconds in the control group (p < 0.001). Mean FCS scores were 0.79 ± 1.34 and 0.21 ± 0.57, respectively (p = 0.001). The DESS score and TFBUT were both associated with the duration of allergic conjunctivitis.

CONCLUSION

The incidence of dry eye assessed by TFBUT was higher in young children with SAC and PAC than in controls. However, subjective symptoms of dry eye (DESS) were inconsistent with objective signs, indicating that close attention should be paid to the evaluation and treatment of dry eye in pediatric population with AC.

Evaporation and Hydrocarbon Chain Conformation of Surface Lipid Films

PURPOSE

The inhibition of the rate of evaporation (R_evap) by surface lipids is relevant to reservoirs and dry eye. Our aim was to test the idea that lipid surface films inhibit R_evap.

METHODS

R_evap were determined gravimetrically. Hydrocarbon chain conformation and structure were measured using a Raman microscope. Six 1-hydroxyl hydrocarbons (11-24 carbons in length) and human meibum were studied. Reflex tears were obtained from a 62-year-old male.

RESULTS

The Raman scattering intensity of the lipid film deviated by about 7 % for hydroxyl lipids and varied by 21 % for meibum films across the entire film at a resolution of 5 μm². All of the surface lipids were ordered. R_evap of the shorter chain hydroxyl lipids were slightly (7%) but significantly lower compared with the longer chain hydroxyl lipids. R_evap of both groups was essentially similar to that of buffer. A hydroxyl lipid film did not influence R_evap over an estimated average thickness range of 0.69 to >6.9 μm. R_evap of human tears and buffer with and without human meibum (34.4 μm thick) was not significantly different. R_evap of human tears was not significantly different from buffer.

CONCLUSIONS

Human meibum and hydroxyl lipids, regardless of their fluidity, chain length, or thickness did not inhibit R_evap of buffer or tears even though they completely covered the surface. It is unlikely that hydroxyl lipids can be used to inhibit R_evap of reservoirs. Our data do not support the widely accepted (yet unconfirmed) idea that the tear film lipid layer inhibits R_evap of tears.

Functional visual acuity assessment of severe atopic keratoconjunctivitis

PURPOSE

To evaluate changes in functional visual acuity (FVA) measurements before and after treatment with 0.1% cyclosporine ophthalmic solution for 3 months in patients with severe atopic keratoconjunctivitis (AKC).

METHODS

Pairs of eyes were analyzed from 3 boys (mean age 9 ± 3.6 years) who complained of having severe AKC and were recruited for the study. Conventional Landolt visual acuity, FVA, and visual maintenance ratio (VMR) measurements were conducted before and after 3 months of 0.1% cyclosporine eye drop treatment. Tear film lipid layer interferometry, tear film break-up time, fluorescein and rose bengal vital stainings, and the Schirmer test were also performed before and after treatment.

RESULTS

Eye drop treatment was associated not only with improvement of tear function and ocular surface status but also with better quality of visual function. The mean logarithm of the minimum angle of resolution FVA and Landolt visual acuity values improved from 0.45 ± 0.26 and 0.13 ± 0.17 before treatment to 0.16 ± 0.03 and -0.06 ± 0.05 after treatment, respectively. Similarly, the mean VMR values were markedly improved from 0.88 ± 0.06 to 0.95 ± 0.03 after treatment.

CONCLUSIONS

FVA and VMR are promising parameters in the assessment of dynamic visual acuity changes in AKC-affected patients and evaluation of treatment outcome.

Evaluation of the tear film instability in children with allergic diseases

CONTEXT

The presence of dry eye syndrome (DES) in ocular allergic diseases was evaluated in several studies. Despite this, little exists about the tear film instability in atopic children including patients with allergic rhinitis (AR), allergic conjunctivitis (AC) and asthma. This is a study which presents intriguing findings regarding the relationship of tear film instability with clinical aspects in atopic children.

OBJECTIVE

To determine the tear film instability in children with AR, AC and asthma.

MATERIALS AND METHODS

One hundred and thirty-five consecutive children with AR, AC and asthma as study group and 45 children without any systemic and ocular abnormality as control group were included in the study. Skin prick tests, measurement of tear film breakup time (TFBUT), serum immunoglobulin E and eosinophil counts were performed in all patients. Also four subgroups of patients were designated as AR group (Group I), AC group (Group II), asthma group (Group III) and control group (Group IV).

RESULTS

Socio-demographic characteristics were similar except for family atopy between the groups (p > 0.05). The mean TFBUT was significantly lower in the study group (15.5 ± 4.4 s) than the control group (18.4 ± 2.9 s; p = 0.000). Also, there was no significant differences in the percentage of the patients who has TFBUT<10 s (p = 0.066). In logistic regression analysis, atopy was found to be the determinant of lower TFBUT (OR = 16.33, 95%; CI = 1.17 to 228.05, p = 0.03).

CONCLUSION

The presence of tear film instability was higher in children with AC, AR and asthma. This finding should be taken in consideration in atopic children.

Downregulation of IL-8, ECP, and total IgE in the tears of patients with atopic keratoconjunctivitis treated with rebamipide eyedrops

Rebamipide eyedrops are approved in Japan for the treatment of dry eye disease. Some patients with allergic conjunctival diseases also manifest dry eye. Earlier we reported that rebamipide suppressed polyI:C-induced inflammatory cytokines in human conjunctival epithelial cells. In the current study we examined the effect of rebamipide eyedrops on the level of interleukin-8 (IL-8), eosinophil cationic protein (ECP), and total IgE on the ocular surface. We prescribed rebamipide eyedrops to patients with atopic keratoconjunctivitis (AKC) who presented with dry eye (6 eyes in 4 AKC patients) and measured the IL-8, ECP, and total IgE levels in their tears before- and 2, and 4-6 weeks after the start of rebamipide treatment. To measure the IL-8 and total IgE levels in their tears we used BD™ CBA Flex sets; ECP measurements were with ELISA. The level of IL-8, ECP, and total IgE in the tears of AKC patients was reduced significantly 4-6 weeks after the start of rebamipide treatment. We also recorded subjective symptoms associated with AKC, e.g. itching, foreign body sensation, and eye mucus discharge, by using a patient questionnaire. Their subjective symptoms associated with AKC were also significantly ameliorated at 2 and 4-6 weeks. Our observations suggest that the anti-inflammatory effects of rebamipide eyedrops help to combat human ocular surface inflammation and that they may be a new effective therapy in patients with AKC.

Sex-steroid imbalance in females and dry eye

Dry eye (DE) is a multifactorial disorder of the ocular surface unit that results in eye discomfort, visual disturbance and ocular surface damage. It is one of the most common complaints in daily ophthalmic practice. The risk of DE increases with age in both sexes, while its incidence is higher among females. In addition, the condition of menopause in aging women may also contribute to DE onset or worsening as a consequence of an overall hormonal imbalance. Sex hormones play a key role in ocular surface physiology and they impact differently on ocular surface tissues. Reduced estrogen levels were historically thought to be responsible in age-related DE onset but more recent investigations have reconsidered the role of androgens that are present and exert a protective function on the ocular surface. Hormone levels themselves, withdrawal changes in hormone levels, and the changes in hormone-receptor responsiveness are all important factors but it remains to be fully elucidated how estrogen or androgen insufficiency act alone or together in a combined imbalance or interplay to raise the risk of disease. The purpose of this review is to briefly outline current scientific evidence on the influence of androgens and estrogens, on the Lachrymal and Meibomian glands and on ocular surface epithelia including conjunctival goblet cells during reproductive and menopausal periods. The role of sex steroids is also discussed in relation to the pathogenesis of different forms of DE and Sjogren's syndrome (SS). The impact of systemic hormone therapy (HT) in DE post-menopausal women still appears as a controversial issue, despite the many clinical studies. Finally, the outcomes of topical applications of steroid-based products are summarized, underlying the need for potential (tear) biomarker(s) in the rationale of DE-targeted therapy.

Usefulness of a new therapy using rebamipide eyedrops in patients with VKC/AKC refractory to conventional anti-allergic treatments

BACKGROUND

Rebamipide, a gastroprotective drug, has been reported to suppress gastric mucosal inflammation. In Japan, rebamipide eyedrops have recently been approved for the treatment of dry eye disease. Some patients with allergic conjunctival diseases such as vernal keratoconjunctivitis (VKC) or atopic keratoconjunctivitis (AKC) manifest dry eye with decreased tear break-up time only. We report patients with VKC/AKC refractory to anti-allergic treatments who responded to the combination of rebamipide eyedrops and conventional anti-allergic treatments with anti-allergic- and/or immunosuppressive/steroid eyedrops.

METHODS

Four patients with allergic conjunctival diseases with giant papillae (VKC or AKC) instilled rebamipide eyedrops three or four times a day for varying periods. All had dry eye with decreased tear break-up time. We evaluated changes in the size of their giant papillae using Image J software.

RESULTS

We observed attenuation of the giant papillae in all 4 patients. In 2 patients with severe disease, whose giant papillae had become larger despite the administration of tacrolimus and steroids, the addition of rebamipide contributed to their attenuation. In 2 patients with mild disease, the giant papillae had become larger or remained the same size despite the administration of anti-allergy drugs; the addition of rebamipide eyedrops also resulted in the attenuation of their giant papillae.

CONCLUSIONS

Our findings suggest that rebamipide eyedrops might attenuate giant papillae in patients with allergic conjunctival diseases and that these eyedrops may be useful for the treatment of not only dry eye but also of allergic conjunctival diseases.

Tear film lipids

Human meibomian gland secretions (MGS, or meibum) are formed from a complex mixture of lipids of different classes such as wax esters, cholesteryl esters, (O-acyl)-ω-hydroxy fatty acids (OAHFA) and their esters, acylglycerols, diacylated diols, free fatty acids, cholesterol, and a smaller amount of other polar and nonpolar lipids, whose chemical nature and the very presence in MGS have been a matter of intense debates. The purpose of this review is to discuss recent results that were obtained using different experimental techniques, estimate limitations of their usability, and discuss their biochemical, biophysical, and physiological implications. To create a lipid map of MGS and tears, the results obtained in the author's laboratory were integrated with available information on chemical composition of MGS and tears. The most informative approaches that are available today to researchers, such as HPLC-MS, GC-MS, and proton NMR, are discussed in details. A map of the meibomian lipidome (as it is seen in reverse phase liquid chromatography/mass spectrometry experiments) is presented. Directions of future efforts in the area are outlined.

Allergic conjunctivitis and dry eye syndrome

BACKGROUND

Allergic conjunctivitis (AC) and dry eye syndrome (DES) are 2 of the most common anterior inflammatory disorders of the ocular surface and one does not preclude the coexistence of the other.

OBJECTIVES

To examine the potential overlap between AC and DES as comorbidities.

METHODS

Using the validated questionnaire known as Subjective Evaluation of Symptom of Dryness, we studied self-reported itchiness, dryness, and redness. In an outpatient optometric setting, 689 patients treated from January 1, 2007, to January 1, 2011, were surveyed for their ocular history and categorized according to their reported level of discomfort of itchiness, dryness, and redness.

RESULTS

Patients ranged in age from 5 to 90 years (median age, 25 years; 39.5% male; 60.5% female). In the studied 689 patients, clinically significant itchiness was found in 194 (28.2%), dry eyes in 247 (35.8%), and redness in 194 (28.2%). Symptom overlap was demonstrated in many of the patients. Of the 194 patients with itchiness, 112 (57.7%) had clinically significant dryness. In the 247 patients with dry eyes, 112 (45.3%) had clinically significant itch. Redness was apparent in 120 of the 194 patients with itch (61.9%) and 122 of the 247 patients with dryness (49.4%). Statistical analysis demonstrated that self-reported itchiness, dryness, and redness were not independent of each other (P<.001; Pearson χ(2) test). The odds of patients with "itchy eyes" also experiencing dry eyes were 2.11 times and the odds of these patients also experiencing redness were 7.34 times that of patients with nonitchy eyes.

CONCLUSIONS

Most patients with "itchy eyes" consistent with AC also have dry eyes and redness. These results suggest that some symptomatic patients concomitantly have features of AC and DES.

Ocular allergy

The eye is probably the most common site for the development of allergic inflammatory disorders, because it has no mechanical barrier to prevent the impact of allergens such as pollen on its surface. Physicians in various specialties and subspecialties who provide some form of primary care frequently encounter various forms of inflammation of the anterior surface of the eye that present as "red eye." However, the eye is rarely the only target for an immediate allergic-type response. Typically, many patients have other combinations of allergic disorders, such as rhinoconjunctivitis, rhinosinusitis, asthma, urticaria, or eczema. Even so, ocular signs and symptoms can frequently be the most prominent features of the entire allergic response for which a patient visits his or her physician. An improved differential diagnosis provides the basis for improved treatment algorithms. Over the past 20 years, we have witnessed an astonishing growth in therapeutic advances, ranging essentially from derivatives of simple aspirin to various newly developed biologic immunomodulatory agents, utilizing implantable drug-delivery devices that exceed the safety and efficacy of those available for other organ systems, and resorting to advanced surgical techniques for the correction of sight-threatening, disease-related complications. Overall, with the expanding knowledge base, the intricacy of ocular inflammation appears to be becoming ever more manageable and, with the team approach between the primary care physician, the ophthalmologist, and the clinical allergist/immunologist, the new "immuno-ophthalmology" approach improves patient outcomes.

An open-label, investigator-masked, crossover study of the ocular drying effects of two antihistamines, topical epinastine and systemic loratadine, in adult volunteers with seasonal allergic conjunctivitis

BACKGROUND

Systemic antihistamines such as loratadine are efficacious in the treatment of many allergic conditions. However, their use has been associated with drying effects, particularly of the ocular surface.

OBJECTIVE

The purpose of this study was to compare the ocular drying effects of topical treatment with epinastine hydrochloride ophthalmic solution 0.05 % twice daily and systemic treatment with loratadine 10 mg once daily in patients with seasonal allergic conjunctivitis through the use of several standard clinical tests for dry eye.

METHODS

This was a single-center, 4-visit, open-label, investigator-masked crossover study in healthy adult volunteers with a history of seasonal allergic conjunctivitis. Participants received 4 days of treatment with topical epinastine administered as 1 drop per eye twice daily and 4 days of treatment with systemic loratadine once daily, with a 10-day washout between treatments. Fluorophotometry was conducted at the baseline visit, at the crossover visit, and after 4 days of each treatment to assess tear volume, tear flow, and tear turnover rate. Decreases from baseline in tear volume, tear flow, or tear turnover rate were considered indicative of a drying effect. Keratitis, global (corneal and conjunctival) fluorescein staining (scale from 0-20 points), and tear film break-up time (TFBUT) were assessed after fluorophotometry at each visit. An increase in keratitis (as measured by global fluorescein staining) and conjunctival lissamine green staining, and a decrease in TFBUT were considered further evidence of a drying effect.

RESULTS

Eighteen subjects were enrolled in and completed the study (78% female; 94% white; age range, 18-55 years). After 4 days of twice-daily use, topical epinastine was associated with no significant changes in tear volume, tear flow, or global fluorescein staining. After 4 days of once-daily use, systemic loratadine was associated with a 33.7% reduction in tear volume (mean reduction, 4.5 microL; range, -7.53 to 22.36 microL; P < 0.05), a 35.0% reduction in tear flow (mean reduction, 0.93 microL/min; range, -2.57 to 2.73 microL/min; P < 0.05), and a 21.7% increase in global fluorescein staining (mean increase, 0.74 point; range, -2.5 to 6.5 points; P < 0.05). No significant change in TFBUT was observed with either treatment.

CONCLUSIONS

These healthy adult volunteers with a history of seasonal allergic conjunctivitis had no clinical signs of ocular drying after 4 days of twice-daily treatment with topical epinastine. After 4 days of once-daily dosing, systemic loratadine was associated with clinical signs of ocular dryness, including decreased tear volume and tear flow. Use of loratadine was also associated with an increase in global fluorescein staining, indicating an increase in ocular surface damage.