Lipid-Containing Lubricants for Dry Eye: A Systematic Review

Efficacy and safety of a lipid-containing artificial tear compared with a non-lipid containing tear: a randomized clinical trial

BACKGROUND

Dry eye disease (DED) is a prevalent condition affecting over 16 million patients in the USA. DED and the symptoms of ocular discomfort are debilitating and a significant burden on patients. If left untreated, DED can progress to cause severe pathology. Treatment is often initiated by patients without consulting a healthcare professional. This study investigated the safety and efficacy of a novel lipid-containing eye drop (BTC), which might better mimic the components of natural tears.

METHODS

This was a multicenter, randomized, double-masked, active control, two arm, parallel group study of eye drops in adult subjects with self-reported DED. Subjects were randomly assigned to BTC or control (commercially available non-lipid eye drops; NLED) arm and were followed for 30 days. Assessments using visual analog scale and patient-reported outcomes (PRO) questionnaires, non-invasive tear break up time, slit-lamp examination, and subject-reported ocular symptoms were conducted at baseline and at days 7 and 30. The primary endpoint was change in overall ocular comfort score from baseline to day 30.

RESULTS

158 subjects were randomized, of whom 130 completed the study per protocol (PP). Mean (SD) age was 47.8 (14.14) years. The mean (95% CI) change in overall comfort scores at the 30-day follow-up in the PP population was 21.4 (15.1, 27.7) for the test drop and 10.0 (3.9, 16.1) for the comparator. The mean (95% CI) treatment difference was 11.3 (2.6, 20.1); this met the pre-defined requirements for non-inferiority. There was no significant difference in the proportion of eyes with reported ocular symptoms between the groups. At day 7, the OR (95% CI) was 0.967 (0.528, 1.770) and at day 30 was 1.160 (0.610, 2.203). There were no Grade 3 or higher corneal edema, corneal neovascularization, corneal staining, conjunctival injection, tarsal abnormalities or any other biomicroscopy findings, and no corneal infiltrates observed during the study.

CONCLUSIONS

The investigational lipid eye drop BTC was noninferior to the commercially available non-lipid comparator in all parameters measured and has the potential to provide an effective therapy for subjects with symptoms of dry eye who would benefit from a lipid-based artificial tear.

TRIAL REGISTRATION

NCT03995355 ( http://www.

CLINICALTRIALS

gov ), registered June 24, 2019.

Patient-Reported Dry Eye Treatment and Burden of Care

OBJECTIVES

Dry eye is a common condition that can decrease the quality of life. This survey-based study of persons with dry eye investigated self-reported treatments (initial, current), out-of-pocket expenses, time spent on self-management, sources of care, and sources of information about their condition.

METHODS

Online dry eye newsletters and support groups were emailed a link to an electronic survey asking members to participate. Survey respondents were not required to answer every question.

RESULTS

In total, 639 persons with self-reported dry eye responded (86% women, 14% men [n=623]; mean ± SD age, 55 ± 14 years [n=595]). Artificial tears were the most reported intervention (76% initially, 71% currently). The median (interquartile range) out-of-pocket treatment cost annually was $500 ($200-$1,320 [n=506]). In addition, 55% (n=544) estimated 5 to 20 min daily on self-management; 22% spent an hour or more. Ophthalmologists provided most dry eye care (67%, n=520). Only 48% (n=524) reported that their primary source of dry eye information came from their eye care clinician.

CONCLUSIONS

Artificial tears are the primary treatment for dry eye. Ophthalmologists provide most dry eye care, but half of patients report that their eye care provider is not their primary source of information. Almost one fourth of patients spend an hour or more daily on treatments.

Lipid-based eye drop formulations for the management of evaporative dry eyes

Dry eye disease is a progressive prevalent ocular surface disorder that arises from various factors and is characterized by insufficient quality and/or quantity of tears. The underlying pathophysiology is intricate and can progress to chronic, difficult-to-treat conditions. Multiple strategies and therapeutic approaches are utilized in its management that target one or more etiopathological components of dry eyes, which may include aqueous tear deficiency or evaporative dry eyes. The primary focus of this paper is on treatment alternatives that utilize lipids for the treatment of evaporative dry eyes. This may arise from either abnormal lipid production or inadequate lipid spreading caused by meibomian gland dysfunction. The hypothesis behind the development of these lipid-containing eye drops is that if they can imitate the lipid layer, they may be able to help in the management of the signs and symptoms of evaporative dry eyes. The lipids used in commercial formulations for dry eyes are mineral oil, castor oil, phospholipids, omega-3 fatty acid, and medium-chain triglycerides. The literature suggests the potential of lipid-containing eye drops to alleviate some of the signs and symptoms and enhance the quality of life for individuals suffering from evaporative dry eyes.

Short-Term Efficacy of Ophthalmic Cyclosporine: A 0.1% Cationic Emulsion in Dry Eye Patients Assessed Under Controlled Environment

INTRODUCTION

To evaluate the short-term efficacy of cyclosporine A (CsA)-0.1% cationic emulsion (CE) in patients with dry eye disease (DED) and mitigation of the inflammatory flares triggered by desiccating stress environments.

METHODS

A single-center non-randomized clinical trial was performed at a tertiary care setting. Twenty patients with DED treated with CsA 0.1% CE were exposed to a normal controlled environment (NCE) (23 °C, 50% relative humidity) and an adverse controlled environment (ACE) (23 °C, 10% relative humidity, 0.43 m/s localized airflow) during baseline and the 1- and 3-month visits. Patients underwent the following evaluations: conjunctival hyperemia and staining, corneal fluorescein staining (CFS) using the Oxford and Cornea and Contact Lens Research Unit (CCLRU) scale, meibomian gland (MG) secretion quality, Dry Eye Questionnaire-5, Symptom Assessment in Dry Eye (SANDE II), and Change in Dry Eye Symptoms Questionnaire. Multivariate models were adjusted for statistical analysis.

RESULTS

Nineteen women and one man (mean age, 58.9 ± 12.3 years) completed the study. All symptom questionnaires, CFS, conjunctival hyperemia and staining, and MG secretion quality improved (p ≤ 0.003) with 1 month of treatment; improvements were maintained after 3 months (p ≤ 0.02), except for SANDE II (p ≥ 0.07). The CFS worsening (total CCLRU) after baseline ACE exposure (from 8.6 to 10.1) was higher, although not significant (p = 0.64), compared with 1 month (from 5.4 to 5.8) and 3 months (from 5.0 to 5.9) after treatment.

CONCLUSION

Topical CsA-0.1% CE improved DED signs and symptoms after 1 month of treatment under controlled environmental conditions. Future studies should confirm the benefit of CsA-0.1% CE in desiccating stress environments.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04492878.

British Society for Rheumatology guideline on management of adult and juvenile onset Sjögren disease

Sjögren disease (SD) is a chronic, autoimmune disease of unknown aetiology with significant impact on quality of life. Although dryness (sicca) of the eyes and mouth are the classically described features, dryness of other mucosal surfaces and systemic manifestations are common. The key management aim should be to empower the individual to manage their condition-conserving, replacing and stimulating secretions; and preventing damage and suppressing systemic disease activity. This guideline builds on and widens the recommendations developed for the first guideline published in 2017. We have included advice on the management of children and adolescents where appropriate to provide a comprehensive guideline for UK-based rheumatology teams.

One Soul and Several Faces of Evaporative Dry Eye Disease

The ocular surface system interacts with, reacts with, and adapts to the daily continuous insults, trauma, and stimuli caused by direct exposure to the atmosphere and environment. Several tissue and para-inflammatory mechanisms interact to guarantee such an ultimate function, hence maintaining its healthy homeostatic equilibrium. Evaporation seriously affects the homeostasis of the system, thereby becoming a critical trigger in the pathogenesis of the vicious cycle of dry eye disease (DED). Tear film lipid composition, distribution, spreading, and efficiency are crucial factors in controlling water evaporation, and are involved in the onset of the hyperosmolar and inflammatory cascades of DED. The structure of tear film lipids, and subsequently the tear film, have a considerable impact on tears' properties and main functions, leading to a peculiar clinical picture and specific management.

Influence of perfluorohexyloctane (Evotears®) on higher order aberrations

PURPOSE

To prospectively assess the effect of regular application of perfluorohexyloctane (F6H8; Evotears®) on the tear film lipid layer, higher order aberrations (HOA) and the repeatability of measurements in healthy eyes.

METHODS

This prospective clinical study included 104 eyes treated with F6H8 four times daily for four weeks (group A) and 101 eyes that served as controls (group B). Measurements were performed with the WASCA aberrometer (Carl Zeiss Meditec GmbH, Jena, Germany). Main outcome measurement in addition to subjective refraction were the root mean square values of HOA measured before and after the intervention.

RESULTS

Regular use of F6H8 over a period of four weeks significantly increases HOA in healthy eyes (p < 0.05). In addition, the repeatability of measurement increases after the application of F6H8.

CONCLUSION

F6H8 may be a suitable treatment option to improve the accuracy of refractive assessment, although it increases HOA. Further studies are needed to confirm the effect on HOA and the repeatability of measurement.

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

A Review on Dry Eye Disease Treatment: Recent Progress, Diagnostics, and Future Perspectives

Dry eye disease is a multifactorial disorder of the eye and tear film with potential damage to the ocular surface. Various treatment approaches for this disorder aim to alleviate disease symptoms and restore the normal ophthalmic environment. The most widely used dosage form is eye drops of different drugs with 5% bioavailability. The use of contact lenses to deliver drugs increases bioavailability by up to 50%. Cyclosporin A is a hydrophobic drug loaded onto contact lenses to treat dry eye disease with significant improvement. The tear is a source of vital biomarkers for various systemic and ocular disorders. Several biomarkers related to dry eye disease have been identified. Contact lens sensing technology has become sufficiently advanced to detect specific biomarkers and predict disease conditions accurately. This review focuses on dry eye disease treatment with cyclosporin A-loaded contact lenses, contact lens biosensors for ocular biomarkers of dry eye disease, and the possibility of integrating sensors in therapeutic contact lenses.

Artificial Tears: A Systematic Review

Artificial tears are the mainstay of dry eye disease management, but also have a role in corneal abrasion and wound healing, pain and inflammation management, conjunctivitis, keratitis, contact lens rewetting and removal, and foreign body removal. A systematic review of randomized controlled trials (PROSPERO registration CRD42022369619) comparing the efficacy of artificial tears in patients with dry eye to inform prescribing choices using Web of Science, PubMed and Medline databases identified 64 relevant articles. There is good evidence that artificial tears improve symptoms of dry eye disease within a month of regular use, applied about four times a day, but signs generally take several months to improve. Not all patients with dry eye disease benefit from artificial tears, so if there is no benefit over a month, alternative management should be considered. Combination formulations are more effective than single active ingredient artificial tears. Artificial tears containing polyethylene glycol are more effective than those containing carboxymethylcellulose/carmellose sodium and hydroxypropyl methylcellulose. Those classified as having evaporative dry eye disease, benefit from artificial tears with liposomes, especially of higher concentration. The data available is limited by the definition of dry eye disease applied in published studies being variable, as well as the disease severity examined and compliance with artificial tears being rarely quantified.

The influence of a mineral oil cationic nanoemulsion or perfluorohexyloctane on the tear film lipid layer and higher order aberrations

PURPOSE

To prospectively assess the effect of a single and regular application of either a cationic nanoemulsion of mineral oil (CN) or perfluorohexyloctane (F6H8) on the lipid layer of the tear film and higher order aberrations (HOA) in patients with Dry Eye Disease (DED).

METHODS

Fifty-seven patients with a lipid layer thickness (LLT) ≤ 75 interferometric colour units (ICU) were included in the study. In group A (20 patients) the effect of a single drop of F6H8 or CN on HOA and LLT was assessed immediately after application and up to two hours later. For long term effects (Group B) 37 patients applied CN or F6H8 five times a day for 12 weeks. Measurement of LLT, HOA, non-invasive-tear-break-up-time (NIBUT) and meibography were assessed prior to as well as at 4 weeks and 12 weeks after initiation of treatment. Our study is registered in the "German Clinical Trials Register" under the trial number: DRKS00028696.

RESULTS

CN led to an increase of the LLT from 46.8 ± 16.9 ICU to 76.3 ± 23.5 ICU (p = 0.021) and to an increase of HOA from 0.43 ± 0.06 μm to 0.48 ± 0.08 μm immediately after application (p = 0.027). There was no correlation between the increase of LLT and HOA (r = -0.04; p = 0.90). In group B an increase of LLT was observed in the F6H8 group from 45.8 ± 8.8 ICU at baseline to 66.7 ± 19.5 ICU at 12 weeks (p = 0.002). No changes of HOA were measured throughout the observation period in group B. After 12 weeks CN increased NIBUT from 9.9 ± 5.3 seconds to 15.5 ± 5.6 seconds (p = 0.04). F6H8 increased NIBUT from 12.4 ± 5.9 seconds to 16.9 ± 4.7 seconds (p = 0.02) after 12 weeks.

CONCLUSION

CN leads to a short-term increase in LLT and HOA, but only immediately after application. In contrast F6H8 does lead to an increase of LLT after regular long-term use but has no effect on HOA. The regular application of lipid-based products does not seem to decrease the quality of vision as measured in HOA. Instead, CN and F6H8, both are able to stabilize the tear film after regular application.

Propylene Glycol and Hydroxypropyl Guar Nanoemulsion - Safe and Effective Lubricant Eye Drops in the Management of Dry Eye Disease

Dry eye disease (DED) is a chronic condition of the ocular surface characterized by a loss of the tear film homeostasis and accompanied by symptoms such as eye discomfort and visual disturbances. DED is classified as aqueous deficient dry eye (ADDE), evaporative dry eye (EDE), and mixed dry eye etiologies. The mainstay treatment in the management of DED is artificial tear drops or lubricant eye drops that replenish the aqueous and/or lipid layer of the tear film. These are available as both lipid-based and non-lipid-based formulations, with/without preservatives. Lipid-based lubricant eye drops can stabilize the tear film lipid layer, reduce tear evaporation, and improve signs of EDE. In this review, we present the formulation components, mechanism of action, and summary of preclinical and clinical evidence on a lipid-based formulation - propylene glycol-hydroxypropyl guar (PG-HPG) nanoemulsion lubricant eye drops (Systane^TM Complete). These eye drops consist of the demulcent (lubricant), PG (0.6%). HPG forms a soft, thin, cross-linked in situ gel matrix with borate ions, when exposed to the tear film, which prolongs lubricant retention and provides ocular surface protection. Dimyristoyl phosphatidyl glycerol, an anionic phospholipid, helps in replenishing the lipid layer of the tear film. Moreover, the nanoemulsion formulation serves as a depot for delivery of dimyristoyl phosphatidyl glycerol to enhance ocular surface coverage. Preclinical and clinical evidence demonstrate that PG-HPG nanoemulsion lubricant eye drops are safe and effective in providing temporary relief of symptoms of DED, regardless of its subtypes. Specifically, it provides sustained reduction in dry eye symptoms, improves tear film stability/lipid layer grade, and improves ocular surface characteristics.

Latest developments on meibomian gland dysfunction: Diagnosis, treatment and management

Background: Meibomian gland dysfunction (MGD) is one of the leading causes of evaporative dry eye disease and one of the most common ophthalmic conditions found in clinical practice. Meibomian gland dysfunction tends to be overlooked because its signs and symptoms do not cause blindness. Meibomian gland dysfunction is characterised by the obstruction of the meibomian gland terminal ducts resulting in tear film instability.Aim: The purpose of this article was to provide an update on MGD’s diagnosis and treatment.Method: A literature review was conducted using search engines such as Google Scholar, Medline and ScienceDirect databases. Keywords such as MGD diagnosis and management and treatment of MGD were used to search the databases.Results: A total of 44 relevant papers were reviewed. These papers were then curated to include only those concerning diagnosis of meibomian gland dysfunction, treatment of meibomian gland dysfunction and management options of meibomian gland dysfunction. The references of individual papers from the curated results were checked to yield a further 13 papers.Conclusion: Meibomian gland dysfunction is not a single entity but is multifactorial in origin; however, our understanding of the condition is evolving rapidly because of newer imaging technology. There is no gold standard treatment option for MGD, but many options are available that include medications and other procedures. 

Management Strategies for Evaporative Dry Eye Disease and Future Perspective

Dry eye disease (DED) is a common disorder that remains challenging from a clinical perspective. Unstable or deficient tear film is a major factor contributing to DED and the inability to resolve the loss of tear film homeostasis that accompanies DED can result in a vicious circle of inflammation and treatment-refractory disease. Recently recognized as a multifactorial disease, the main etiological subtypes of DED are aqueous-deficient and evaporative which exist on a continuum, although evaporative dry eye (EDE) is the more frequent classification. Although attaining greater recognition in recent years, there is currently no consensus and no clear recommendation on how to manage EDE. Clarity on the early diagnosis and treatment of EDE may facilitate the avoidance of progression to chronic inflammation, permanent damage to the ocular surface, and treatment-refractory disease. The purpose of this review was to identify current best practice for management of EDE in order to help clinicians in providing accurate diagnosis and optimized treatment. We summarize recent literature considering the role of the lipid layer on tear film stability, the importance of its composition and of its dynamic behavior, and the link between its malfunction and the insurgence and maintenance of tear film-related diseases. We have provided an assessment of the best management of lipid-deficient EDE based upon an understanding of disease pathophysiology, while indicating the flow of current treatments and possible future evolution of treatment approaches. Lipid containing eye drops may be considered as a step closer to natural tears from artificial aqueous tears because they more closely mimic the aqueous and lipid layers and may be used in combination with other management approaches. As a next step, we recommend working with a wider expert group to develop full guidelines to enable patient-centered management of EDE. Key pointsDry eye is a multifactorial disease of variable presentation with the tendency to become a chronic disease for which it is essential to identify and treat the main pathogenic mechanisms involved and tailor the treatment to the individual patient.Early intervention is needed to prevent the vicious cycle of DED and may require a multi-faceted management approach.EDE is not just a problem of MGD but can be the result of anything affecting blinking, mucin spreading, aqueous layer volume and content.Lipid-containing eye drops may provide significant relief of symptoms by improving the lipid layer and its spreading ability and, as such, are an appropriate component of the overall management of lipid-deficient EDE; natural lipid-containing eye drops should be the preferred treatment.

A Practical Approach to Severity Classification and Treatment of Dry Eye Disease: A Proposal from the Mexican Dry Eye Disease Expert Panel

Dry eye disease (DED) has a higher prevalence than many important systemic disorders like cardiovascular disease and diabetes mellitus, representing a significant quality of life burden for the affected patients. It is a common reason for consultation in general eye clinics worldwide. Nowadays, the diagnostic and therapeutic approach at the high corneal and ocular surface specialty level should be reserved for cases of severe and chronic dry eye disease associated with systemic autoimmune diseases or complicated corneal and ocular surface pathologies. In such cases, the diagnostic and therapeutic approach is often complex, elaborate, time-consuming, and costly due to the use of extensive dry eye questionnaires, noninvasive electronic diagnostic equipment, and clinical laboratory and ancillary tests. However, other eye care specialists attend a fair amount of DED cases; therefore, its diagnosis, classification, and management should be simple, practical, achievable, and effective. Considering that many patients attending non-specialized dry eye clinics would benefit from better ophthalmological attention, we decided to elaborate a practical DED classification system based on disease severity to help clinicians discriminate cases needing referral to subspecialty clinics from those they could attend. Additionally, we propose a systematic management approach and general management considerations to improve patients' therapeutic outcomes according to disease severity.

Omega-9 fatty acids: potential roles in inflammation and cancer management

Background

Omega-9 fatty acids represent one of the main mono-unsaturated fatty acids (MUFA) found in plant and animal sources. They are synthesized endogenously in humans, though not fully compensating all body requirements. Consequently, they are considered as partially essential fatty acids. MUFA represent a healthier alternative to saturated animal fats and have several health benefits, including anti-inflammatory and anti-cancer characters.

The main body of the abstract

This review capitalizes on the major omega-9 pharmacological activities in context of inflammation management for its different natural forms in different dietary sources. The observed anti-inflammatory effects reported for oleic acid (OA), mead acid, and erucic acid were directed to attenuate inflammation in several physiological and pathological conditions such as wound healing and eye inflammation by altering the production of inflammatory mediators, modulating neutrophils infiltration, and altering VEGF effector pathway. OA action mechanisms as anti-tumor agent in different cancer types are compiled for the first time based on its anti- and pro-carcinogenic actions.

Conclusion

We conclude that several pathways are likely to explain the anti-proliferative activity of OA including suppression of migration and proliferation of breast cancer cells, as well stimulation of tumor suppressor genes. Such action mechanisms warrant for further supportive clinical and epidemiological studies to confirm the beneficial outcomes of omega-9 consumption especially over long-term intervention.

Assessment and Management of Dry Eye Disease and Meibomian Gland Dysfunction: Providing a Singapore Framework

ABSTRACT

The purpose of this article is to provide a framework for general ophthalmologists in Singapore to manage dry eye. This framework considers the evidence in the literature as well as recommendations from expert panels such as the Tear Film & Ocular Surface Society Dry Eye Workshop II and the Asia Cornea Society Workgroup.This article covers the assessment of patient medical history and ask triage questions to identify local and systemic causes of dry eye disease (DED), excluding other possible causes, as well as the risk factors for DED and ocular surface inflammation. Evaluation of clinical signs to establish the diagnosis of DED and differentiation from other causes of irritable, red eyes are described. Tests for understanding the underlying disease processes and severity of DED are also presented.Management of dry eye should involve patient education and engagement. Information about the natural history and chronic nature of DED should be provided to improve long-term management of the disease and enhance compliance. Aggravating factors should be removed or lessened.We provide a guide to determine the most appropriate treatment (or combination of treatments) based on the severity and cause(s) of the disease, as well as the patient's needs and preferences. The aim of the management is to relieve ocular discomfort and prevent worsening of symptoms and signs, as well as to optimize visual function and minimize structural ocular damage. We also discuss the systematic follow-up and assessment of treatment response, as well as monitoring side effects of treatment, bearing in mind continuous support and reassurance to patients.

Effect of Eye Spray Phospholipid Concentration on the Tear Film and Ocular Comfort

OBJECTIVES

To evaluate the effect of eye spray phospholipid concentration on symptoms and tear film stability.

METHODS

High-concentration (Tears Again, Optima Pharma GmbH, Hallbergmoos, Germany) and low-concentration (Ocuvers, Innomedis AG, Germany) phospholipid eye sprays were sprayed onto the closed eyelids of 30 subjects (33.2±1.8 years; 20 women) in a multicentered, prospective, crossover study. Ocular comfort (visual analog scale) and noninvasive tear film stability (NIBUT) of each eye were evaluated before application (along with the Ocular Surface Disease Index), 10 min after application, and 30 min after application.

RESULTS

Comfort (high concentration: 68.5±16.4 vs. low concentration: 70.7±14.5 phospholipid) and NIBUT (high concentration: 11.5±4.6 sec vs. low concentration: 11.2±6.0 sec phospholipid) were not different (P>0.3) between sprays before application, but comfort (by 12 points, P=0.001) and NIBUT (by 5 sec, P=0.016) were significantly better with a high-concentration phospholipid spray at both 10 min and 30 min time points than those with the low-concentration phospholipid spray.

CONCLUSIONS

The liposomal eye spray with higher concentration of phospholipids significantly improved ocular comfort and tear film stability in contrast to the eye spray with lower concentration of phospholipids, hence practitioners need to choose an appropriate eye spray to maximize the patient benefit.

Relieving the symptoms of dry eye disease: update on lubricating eye drops containing hydroxypropyl-guar

Hydroxypropyl-guar (HPG) is a thickening agent first added to lubricating eye drops in 2003. This agent, which enhances viscosity, has been used in the SYSTANE® family of lubricant eye drops (Alcon Laboratories, Inc., Fort Worth, TX, USA). HPG forms a partially linked gel with borate to prolong the retention of demulcents, such as polyethylene glycol and propylene glycol, on the eye. This helps to protect the ocular surface, thereby reducing the symptoms of dry eye disease (DED). The definition of DED has evolved with advances in research, leading to changes in HPG-containing eye care solutions. This article reviews current knowledge on the use of HPG-containing lubricating eye drops in the management of DED.

Recent Progress in Cartilage Lubrication

Healthy articular cartilage, covering the ends of bones in major joints such as hips and knees, presents the most efficiently-lubricated surface known in nature, with friction coefficients as low as 0.001 up to physiologically high pressures. Such low friction is indeed essential for its well-being. It minimizes wear-and-tear and hence the cartilage degradation associated with osteoarthritis, the most common joint disease, and, by reducing shear stress on the mechanotransductive, cartilage-embedded chondrocytes (the only cell type in the cartilage), it regulates their function to maintain homeostasis. Understanding the origins of such low friction of the articular cartilage, therefore, is of major importance in order to alleviate disease symptoms, and slow or even reverse its breakdown. This progress report considers the relation between frictional behavior and the cellular mechanical environment in the cartilage, then reviews the mechanism of lubrication in the joints, in particular focusing on boundary lubrication. Following recent advances based on hydration lubrication, a proposed synergy between different molecular components of the synovial joints, acting together in enabling the low friction, has been proposed. Additionally, recent development of natural and bio-inspired lubricants is reviewed.

Therapeutic potential of castor oil in managing blepharitis, meibomian gland dysfunction and dry eye

The multifactorial pathogenesis and interrelationship of blepharitis, meibomian gland dysfunction and dry eye disease poses challenges to any therapeutic approach. Current treatments are mostly palliative, with success limited by perceived inefficacy and poor patient compliance. Castor oil, a natural derivative of the Ricinus communis plant, is widely used as an emollient in cosmetics and personal care products, drug delivery systems and wound dressings. Castor oil is deemed safe and tolerable, with strong anti-microbial, anti-inflammatory, anti-nociceptive, analgesic, antioxidant, wound healing and vaso-constrictive properties. Its main constituent, ricinoleic acid, has a bipolar molecular structure that promotes the formation of esters, amides and polymers. These can supplement deficient physiological tear film lipids, enabling enhanced lipid spreading characteristics and reducing aqueous tear evaporation. Studies reveal that castor oil applied topically to the ocular surface has a prolonged residence time, facilitating increased tear film lipid layer thickness, stability, improved ocular surface staining and symptoms. This review summarises the properties, current uses of, and therapeutic potential of castor oil in managing ocular surface disease. The biochemical, medicinal actions of castor oil are explored from the perspective of ocular surface pathology, and include microbial and demodectic over-colonisation, inflammatory and oxidative processes, as well as clinical signs and symptoms of dryness and discomfort.

Comparative Evaluation in Intense Pulsed Light Therapy Combined with or without Meibomian Gland Expression for the Treatment of Meibomian Gland Dysfunction

OBJECTIVE

To determine whether the combination of meibomian gland expression (MGX) with intense-pulsed light (IPL) has a better efficacy to treat meibomian gland dysfunction (MGD) than IPL alone.

METHODS

One hundred patients with MGD were randomly divided into three groups: MGX, IPL, and IPL+ MGX. Clinical parameters included the Ocular Surface Disease Index (OSDI), tear meniscus height (TMH), noninvasive keratograph tear breakup time (NIBUT), redness, meibomian gland dropout, tear breakup time (TBUT), corneal fluorescent staining (CFS), eyelid margin score, meibomian gland secretion function, and Schirmer I tests were collected before treatment and at 1 and 3 months after treatment. Compare the indexes of each group before and after treatment and also compare the differences of each group on follow-up.

RESULTS

Compared to the baseline, OSDI, TBUT, and meibomian gland secretion function in IPL group improved throughout the follow-up period (all P < .05) and part of the meibomian gland secretion function increased continuously. OSDI, TBUT, lower eyelid margin scores, and meibomian gland secretion function in IPL + MGX group improved at the both follow-up visits (all P < .05), and continued improvement in meibomian gland secretion function can be observed. Lower meibomian gland dropout and CFS reduced at 1 month and 3 months respectively in IPL ± MGX group (P = .001,P = .001).Compared to IPL group, only CFS has reduction in IPL + MGX group at 1-month (P < .001), CFS, upper and lower MGYCS were improved at the 3 months (P = .037,P = .014, P = .049).

CONCLUSIONS

MGX may have synergistic effect when combined with IPL therapy, and the effect can last at least 3 months.

An Evidence-Based Strategic Approach to Prevention and Treatment of Dry Eye Disease, a Modern Global Epidemic

Dry eye disease (DED) is an emerging health concern causing significant visual, psychological, social, and economic impact globally. In contrast to visual rehabilitation undertaken at late stages of DED, measures instituted to prevent its onset, establishment, or progression can alter its natural course and effectively bring down the associated morbidity. This review attempts to present the available literature on preventive strategies of DED at one place, including strategies for risk assessment and mitigation, targeting a wide range of population. A literature search was conducted using PubMed and an extensive literature review on preventive strategies for DED was compiled to put forth a holistic and strategic approach for preventing DED. This can be undertaken at various stages or severity of DED directed at different tiers of the health care system. Conclusion: This review intends to put emphasis on preventive strategies being adopted as an integral part of routine clinical practice by general ophthalmologists and specialists to tackle the burden of DED and improve the quality of the lives of the patients suffering from it.

Crosslinked hyaluronic acid with liposomes and crocin for management symptoms of dry eye disease caused by moderate meibomian gland dysfunction

AIM

To study the effect of uncrosslinked and crosslinked hyaluronic acid combined with other artificial tear components in patients with dry eye caused by moderate meibomian gland dysfunction.

METHODS

Prospective, single-blind, contralateral eye study. Fifty eyes (25 patients) were analyzed. Eye selection for each tear type was random, and the eye drop formulations, 0.4% uncrosslinked hyaluronic acid and 0.2% galactoxyloglucan (tear A) and 0.15% crosslinked hyaluronic acid, crocin, and liposomes (tear B) were used. The determined dosing schedule was three times a day for six weeks, and the study participants underwent a clinical examination before and 45d after lubricant treatment. The Schirmer test, tear breakup time (TBUT) test, and Ocular Surface Disease Index (OSDI) questionnaire were applied before and after instillation period with both types of artificial tears.

RESULTS

On the Schirmer test, a significant improvement was obtained with both tear A (P<0.01) and tear B (P<0.01). On the TBUT test, a significant improvement was obtained with tear A (P<0.01) and tear B (P<0.01). The OSDI score significantly decreased after instillation period with both artificial tear types (P<0.01).

CONCLUSION

Uncrosslinked hyaluronic acid combined with other components, such as tamarind seed polysaccharide, and crosslinked hyaluronic acid combined with liposomes and crocin are effective for management symptoms of dry eye disease.

Effects of Aqueous-Supplementing Artificial Tears in Wearers of Biweekly Replacement Contact Lenses vs Wearers of Daily Disposable Contact Lenses

PURPOSE

To compare the effects of artificial tears (ATs) in wearers of biweekly replacement silicone hydrogel contact lenses (BW-Ws) and wearers of daily disposable contact lenses (DD-Ws) of the same material.

MATERIALS AND METHODS

The aqueous-supplementing ATs, OPTOyalA and OPTOidro, were assigned to be used for 2 weeks to healthy and young subjects: 1) 20 (8 and 12, respectively) BW-Ws wearing silicone hydrogel somofilcon A CLs (Clariti Elite), 2) 18 (9 and 9, respectively) DD-Ws wearing silicone hydrogel somofilcon A CLs (Clarity 1 Day), and 3) a control group of 33 (16 and 17, respectively) N-Ws. Ocular symptoms and comfort, tear volume and stability, and ocular surface condition were assessed by Ocular Surface Disease Index (OSDI), 5-Item Dry Eye Questionnaire (DEQ5), tear meniscus height (TMH), non-invasive tear break-up time (NIBUT), and evaluation of ocular redness (OR). The assessment was performed before and after 15 days of use of the ATs in the 3 groups (BW-Ws, DD-Ws, and N-Ws).

RESULTS

No clear significant difference was noted in symptoms and signs between OPTOyalA and OPTOidro irrespectively of the group of people studied. ATs use for 15 days produced a significant improvement in DEQ5 and OR in DD-Ws (Δ=-34%, p=0.006; Δ=-23%, p<0.001) and in N-Ws (Δ=-21%, p=0.001; Δ=-10%, p=0.006) but not in BW-Ws (Δ=-5%, p=0.072; Δ=-2%, p=0.257). No significant change was noted for TMH.

CONCLUSION

In young and healthy subjects, the aqueous-supplementing effect of the ATs under consideration is more a rinsing and tear replacem ent effect than an increase in tear volume, and it produces an improvement of the eye redness and ocular symptoms. Contact lens wear influenced the effectiveness of ATs in a way which is correlated with the CL replacement schedule.

Reliability of the Evidence Addressing Treatment of Corneal Diseases: A Summary of Systematic Reviews

Importance

Patient care should be informed by clinical practice guidelines, which in turn should be informed by evidence from reliable systematic reviews. The American Academy of Ophthalmology is updating its Preferred Practice Patterns (PPPs) for the management of the following 6 corneal diseases: bacterial keratitis, blepharitis, conjunctivitis, corneal ectasia, corneal edema and opacification, and dry eye syndrome.

Objective

To summarize the reliability of the existing systematic reviews addressing interventions for corneal diseases.

Data Source

The Cochrane Eyes and Vision US Satellite database.

Study Selection

In this study of published systematic reviews from 1997 to 2017 (median, 2014), the Cochrane Eyes and Vision US Satellite database was searched for systematic reviews evaluating interventions for the management of any corneal disease, combining eyes and vision keywords and controlled vocabulary terms with a validated search filter.

Data Extraction and Synthesis

The study classified systematic reviews as reliable when each of the following 5 criteria were met: the systematic review specified eligibility criteria for inclusion of studies, conducted a comprehensive literature search for studies, assessed risk of bias of the individual included studies, used appropriate methods for quantitative syntheses (meta-analysis) (only assessed if meta-analysis was performed), and had conclusions that were supported by the results of the systematic review. They were classified as unreliable if at least 1 criterion was not met.

Main Outcomes and Measures

The proportion of systematic reviews that were reliable and the reasons for unreliability.

Results

This study identified 98 systematic reviews that addressed interventions for 15 corneal diseases. Thirty-three of 98 systematic reviews (34%) were classified as unreliable. The most frequent reasons for unreliability were that the systematic review did not conduct a comprehensive literature search for studies (22 of 33 [67%]), did not assess risk of bias of the individual included studies (13 of 33 [39%]), and did not use appropriate methods for quantitative syntheses (meta-analysis) (12 of 17 systematic reviews that conducted a quantitative synthesis [71%]). Sixty-five of 98 systematic reviews (66%) were classified as reliable. Forty-two of the 65 reliable systematic reviews (65%) addressed corneal diseases relevant to the 2018 American Academy of Ophthalmology PPPs; 33 of these 42 systematic reviews (79%) are cited in the 2018 PPPs.

Conclusions and Relevance

One in 3 systematic reviews addressing interventions for corneal diseases are unreliable and thus were not used to inform PPP recommendations. Careful adherence by systematic reviewers and journal editors to well-established best practices regarding systematic review conduct and reporting might help make future systematic reviews in eyes and vision more reliable.

Evaluation of use of essential fatty acids in topical ophthalmic preparations for dry eye

PURPOSE

Essential fatty acids (EFAs) as dietary supplements are used in treating dry-eye for reducing inflammation at the ocular surface. Their topical application in eye drops to deliver fatty acid (FA) directly to the ocular surface requires thorough investigation. Being lipids in nature EFAs can interact with tear lipids and affect tear stability. This study aimed at investigating the biophysical interactions of EFAs with Meibomian lipids.

METHODS

Rheology of mixtures of Human Meibomian lipids with EFAs (LA-linoleic acid, ALA-alpha-linolenic acid), OA (oleic acid), and GLA (gamma-linolenic acid) was studied using Langmuir trough technology on an artificial tear solution at the ocular surface temperature. Pressure-area profiles were used to determine compressibility and elasticity of the mixed films.

RESULTS

LA enhanced spreading of Meibomian lipids and increased their compressibility and elasticity which can be beneficial for tear stability. ALA condensed Meibomian lipids film with less elasticity deemed unfavourable for tear stability. OA expanded Meibomian lipids but decreased elasticity at high compressions making films less stable. GLA had little or no favourable effect on tear stability. Higher concentrations of FAs made films less stable.

CONCLUSIONS

EFAs or OA in topical ophthalmic preparations can affect spread and stability of the tear film lipid layer. Rheology of mixed films should be tested using Langmuir trough technology to determine suitable type and amount of a lipid additive for therapeutic eye drops. In topical applications, the omega-6 LA (not omega-3 FA) at low concentrations (20 mol%) can be beneficial for enhancing tear stability in dry eye patients.

Management of congenital ichthyoses: European guidelines of care, part two

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016, and a consensus on the discussions. These guidelines summarize evidence and expert-based recommendations and intend to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part two, covering the management of complications and the particularities of some forms of congenital ichthyosis.

Preclinical Evaluation of a New Hydroxypropyl-Guar Phospholipid Nanoemulsion-Based Artificial Tear Formulation in Models of Corneal Epithelium

PURPOSE

To evaluate the effect of hydroxypropyl-guar anionic phospholipid nanoemulsion (HP-guar nanoemulsion), a new artificial tear formulation for treatment of dry eye disease (DED), in corneal epithelium models.

METHODS

Cultured human corneal epithelial cells were used to assess (1) hydration protection and hydration retention protection against desiccation, and (2) cell recovery after benzalkonium chloride (BAC) damage. Corneal epithelium permeability was measured by 5,6-carboxyfluorescein (CF) uptake in intact rabbit eyes. Lubricity was determined using simulated blinking in bovine pericardium-pericardium tribological experiments; elastic filament strength was measured using an extensional rheometer. Comparator arms included vehicle/control and the microemulsion [Systane^® Balance (SYSB)].

RESULTS

Cell hydration protection was 39.5%, 7.1%, and -0.1%, and surface hydration retention was 32.6%, 11.0%, and -1.2% with HP-guar nanoemulsion, SYSB, and vehicle, respectively, after desiccation. After 48 h, cell recovery from BAC exposure (relative fluorescence units ± SD) was faster with HP-guar nanoemulsion treatment (2.66 ± 0.2) than SYSB (2.76 ± 0.2) and vehicle (3.11 ± 0.4). The CF permeability (ng CF/g) decreased in rabbit cornea treated with HP-guar nanoemulsion (9.6 ± 2.3) than those with SYSB (13.12 ± 2.8) or BAC-exposed cornea (22.6 ± 5.1). HP-guar nanoemulsion demonstrated greater lubricity and polymer filament break-up time than SYSB and vehicle. In all assessments, HP-guar nanoemulsion showed significant improvement versus vehicle/control (P < 0.05); outcomes were better with HP-guar nanoemulsion versus microemulsion.

CONCLUSIONS

The HP-guar nanoemulsion promotes greater moisture retention, protection, improved cell barrier function, and increased elastic filament strength in corneal epithelium models. The potential clinical benefits of HP-guar nanoemulsion needs to be evaluated in patients with DED, in future studies.

Topical Cyclosporine Pretreatment of Ocular Surface in Allogeneic Hematopoietic Stem Cell Transplant Recipients

PURPOSE

Dry eye disease (DED) of ocular graft-versus-host disease (GVHD) is a common complication after allogeneic hematopoietic stem cell transplantation (HSCT). Ongoing inflammation and irreversible fibrotic changes of the ocular surface and adnexa are obstacles for effective treatment of ocular GVHD. We hypothesized that topical cyclosporine A (CsA) pretreatment might be effective in preventing ocular GVHD.

METHODS

In this prospective, randomized, comparative study, patients were randomly assigned to the topical CsA treatment (4 times daily in both eyes for a month before allogeneic HSCT and continued use of eye drops after transplantation) or control (no treatment) groups. Participants underwent thorough ophthalmic examination-including Ocular Surface Disease Index questionnaire survey, Schirmer test, tear break-up time (TBUT) evaluation, and corneal fluorescein staining-before and 1, 2, and 3 months after allogeneic HSCT.

RESULTS

Fifty-eight participants completed the study. Among patients with baseline Schirmer values <10 mm and TBUT <5 s before allogenic HSCT, those in the topical CsA treatment group exhibited significantly better corresponding values after transplantation than patients in the control group.

CONCLUSIONS

Topical CsA pretreatment might be beneficial in the early stage of DED and might prevent further inflammation and consequent irreversible fibrosis, especially in patients with preexisting DED components.

Association between dry eye symptoms and signs

Purpose

To evaluate the association between subjective dry eye symptoms and the results of the clinical examinations.

Methods

The study was a clinical-based survey involving 215 first-year students selected consecutively during a regular ocular health examination at the University of Cape Coast Optometry Clinic. The data collection process spanned for a period of four months. Out of the 215 students, 212 returned their completed questionnaires and were subsequently included in the study. Dry eye tests including meibomian gland assessment, tear break up time, fluorescein staining, Schirmer test, and blink rate assessment, were performed on each subject after completion of the Ocular Surface Disease Index (OSDI) questionnaire. Shapiro–Wilk test was used to determine the normality of the clinical tests, and Spearman's correlations co-efficient was used to determine the correlations between the clinical test results and dry eye symptoms.

Results

Statistically significant associations were found between OSDI scores and blink rate (r_s = 0.140; P < 0.042), and associations between OSDI scores and contrast sensitivity scores (r_s = 0.263; P < 0001). However, the results of corneal staining (r_s = −0.006; P < 0.926), Schirmer test (r_s = −0.033; P = 0.628), tear break up time (r_s = −0.121; P < 0.078), meibomian gland expressibility (r_s = 0.093; P < 0.180), and meibomian gland quality (r_s = 0.080; P < 0.244) showed no significant association with OSDI. The correlation coefficients range from −0.006 to 0.263 showed low to moderate correlation between dry eye symptoms and the results of clinical test.

Conclusion

Associations between dry eye symptoms and clinical examinations are low and inconsistent, which may have implications for the diagnoses and treatment of dry eye disease.

Tear film evaluation and management in soft contact lens wear: a systematic approach

The human tear film is a highly ordered structure consisting of a thin layer of lipid on the surface and a thicker aqueous-mucin phase, which increases in mucin concentration toward the corneal epithelial cell layer. The health of the tear film and ocular surface influences the likelihood of being able to achieve successful contact lens wear. Contact lens discomfort and dryness are the most frequent reasons why contact lens wearers experience reduced wearing times, which can eventually lead to contact lens discontinuation. Comprehensive clinical assessment of tear film integrity and ocular surface health is therefore essential prior to commencing contact lens wear, to enable the ocular surface environment to be optimised to support lens wear. These parameters should also be evaluated over the course of contact lens wear, in order to identify any aspects requiring clinical management and ensure maintenance of optimal lens-wearing conditions. This review summarises current knowledge relating to the effects of soft contact lens wear on the tear film and ocular surface. It also provides a systematic approach to evaluating tear film and ocular surface integrity, in order to guide the clinical management of tear film anomalies with respect to contact lens wear.

The Effect of Optive and Optive Advanced Artificial Tears on the Healthy Tear Film

PURPOSE

To evaluate the impact of Optive (Allergan, Irvine, CA) and Optive Advanced (Allergan, Irvine, CA) on tear film stability and quality during a one-hour observation period when compared to saline (Pfizer, Perth, WA).

METHODS

This was a double-masked, cross-over study. Twenty participants attended three visits, randomly receiving either Optive, Optive Advanced or saline. Oculus Keratograph 5M (Oculus, Arlington, WA, USA), non-invasive keratograph break-up time (NIKBUT), Lipiview (TearScience Inc, Morrisville, NC, USA), lipid layer thickness (LLT) and comfort were measured prior to and 5, 15 and 60 min after drop instillation.

RESULTS

Optive Advanced demonstrated a significant increase in LLT between baseline (57.5 ± 12.3 nm) and both 5 min (67.5 ± 18.8 nm, p = 0.04) and 15 min (68.9 ± 17.3 nm, p = 0.04) but not 60 min (61.6 ± 14.3 nm, p = 0.47). Optive and saline were not different between timepoints for LLT (p > 0.05). There was no difference between timepoints for any of the drops for NIKBUT (p = 0.75). Comfort was significantly better at 5 min compared to baseline for Optive (8.3 ± 1.2 and 7.3 ± 1.4, respectively, p = 0.03) but not different for Optive Advance or saline (p > 0.05).

CONCLUSIONS

Optive Advanced increased LLT for 15 min following instillation, returning to baseline within one hour. This did not however, translate into an improvement in tear film stability over this time period. Only Optive demonstrated an improvement in comfort.

Relevance of Lipid-Based Products in the Management of Dry Eye Disease

Components of the ocular surface synergistically contribute to maintaining and protecting a smooth refractive layer to facilitate the optimal transmission of light. At the air-water interface, the tear film lipid layer (TFLL), a mixture of lipids and proteins, plays a key role in tear surface tension and is important for the physiological hydration of the ocular surface and for ocular homeostasis. Alterations in tear fluid rheology, differences in lipid composition, or downregulation of specific tear proteins are found in most types of ocular surface disease, including dry eye disease (DED). Artificial tears have long been a first line of treatment in DED and aim to replace or supplement tears. More recently, lipid-containing eye drops have been developed to more closely mimic the combination of aqueous and lipid layers of the TFLL. Over the last 2 decades, our understanding of the nature and importance of lipids in the tear film in health and disease has increased substantially. The aim of this article is to provide a brief overview of our current understanding of tear film properties and review the effectiveness of lipid-based products in the treatment of DED. Liposome lid sprays, emulsion eye drops, and other lipid-containing formulations are discussed.

Tear lipid supplement prophylaxis against dry eye in adverse environments

PURPOSE

To compare the prophylactic efficacy of single application of lipid and non-lipid containing tear supplements, prior to exposure of symptomatic dry eye subjects to a simulated adverse environment.

METHODS

Thirty subjects with mild-to-moderate dry eye symptoms participated in the prospective, randomised, double-masked, paired-eye trial. A lipomimetic drop (Systane^® Balance) was applied to one eye (randomised), and a non-lipid containing drop (Systane^® Ultra) applied simultaneously to the contralateral eye. Subjects were subsequently exposed to a validated simulated adverse environment model created by a standing fan directed towards the eye, at a distance of 1m, for 2.5min. Low contrast glare acuity, lipid layer grade (LLG), non-invasive tear break-up time (NIBUT), temperature variation factor (TVF), and tear meniscus height (TMH) were evaluated at baseline, following eye drop instillation and following simulated adverse environment exposure.

RESULTS

Both therapies resulted in increased NIBUT (both p<0.001), and prevented its decline below baseline with simulated adverse environment exposure (both p>0.05). However, only the lipomimetic drop increased LLG (p<0.001) and precluded its fall below baseline post-adverse environment exposure (p=0.15). Furthermore, post-instillation and post-exposure LLGs and NIBUT were significantly higher in the lipomimetic group (all p<0.05). No significant changes were observed in glare acuity, TVF and TMH (all p>0.05). More subjects (67%) reported greater ocular comfort in the eye receiving the lipomimetic.

CONCLUSIONS

Single application of both lipid and non-lipid containing eye drops conferred protective effects against exposure to adverse environmental conditions in subjects with mild-to-moderate dry eye, although the lipomimetic demonstrated superior prophylactic efficacy.

Lipid Supplements and Clinical Aspects of Tear Film in Habitual Lens Wearers

PURPOSE

To establish the effect of lipid supplements on the tear lipid layer and their influence on lens wear comfort in habitual lens wearers.

METHODS

Forty habitual soft contact lens wearers were recruited to a double-masked, randomized crossover trial. An emulsion drop containing phosphatidylglycerine (Systane Balance; Alcon) and a saline drop as a placebo or a liposomal spray containing phosphatidylcholine (Tears again; BioRevive) and a saline spray as a placebo were used three times a day for 2 weeks with 48 hours washout between each intervention. Ocular comfort, lipid layer grade, and stability of the tear film using a Tearscope and tear evaporation rate using a modified VapoMeter were assessed after 6 hours of lens wear with lenses in situ.

RESULTS

Neither of the lipid supplements improved lens wear comfort compared to baseline. The noninvasive surface drying time significantly reduced with the placebo spray at day 1 (P = .002) and day 14 (P = .01) whereas the lipid spray had no effect. With the lipid drop and placebo, noninvasive surface drying time was unchanged compared to baseline (P > .05) on day 1, but by day 14, noninvasive surface drying time was reduced with the lipid drop (P = .02) and placebo (P < .001). Symptomatic wearers showed shorter noninvasive surface drying time compared to asymptomatic wearers with the spray treatment on both days (P = .03) but not with the lipid drop (P = .64). The placebo drop significantly changed the lipid layer distribution (P = .03) with a higher percentage of thinner patterns compared to the baseline distribution at day 14. A weak but significant correlation was shown between ocular comfort and noninvasive surface drying time (r = -0.21, P = .003) and tear evaporation rate (r = 0.19, P = .008). Ocular comfort was not associated with lipid layer patterns (r = 0.13, P = .06).

CONCLUSIONS

Ocular comfort during contact lens wear improved with increased tear film stability and a reduced tear evaporation rate. However, the lipid supplements did not improve ocular comfort from baseline.

Emerging strategies for the diagnosis and treatment of meibomian gland dysfunction: Proceedings of the OCEAN group meeting

Meibomian gland dysfunction (MGD) is a common and chronic disorder that has a significant adverse impact on patients' quality of life. It is a leading cause of evaporative dry eye disease (DED), as meibomian glands play an important role in providing lipids to the tear film, which helps to retard the evaporation of tears from the ocular surface. MGD is also often present in conjunction with primary aqueous-deficient DED. Obstructive MGD, the most commonly observed type of MGD, is the main focus of this article. MGD is probably caused by a combination of separate conditions: primary obstructive hyperkeratinization of the meibomian gland, abnormal meibomian gland secretion, eyelid inflammation, corneal inflammation and damage, microbiological changes, and DED. Furthermore, skin diseases such as rosacea may play a part in its pathology. Accurate diagnosis is challenging, as it is difficult to differentiate between ocular surface diseases, but is crucial when choosing treatment options. Ocular imaging has advanced in recent years, providing ophthalmologists with a better understanding of ocular diseases. This review presents a literature update on the 2011 MGD workshop and an optimized approach to accurate diagnosis of MGD using currently available methods and tests. It also outlines the emerging technologies of interferometry, non-contact meibography, keratography and in vivo confocal laser microscopy, which offer exciting possibilities for the future. Selected treatment options for MGD are also discussed.

Nanoparticles and nanofibers for topical drug delivery

This review provides the first comprehensive overview of the use of both nanoparticles and nanofibers for topical drug delivery. Researchers have explored the use of nanotechnology, specifically nanoparticles and nanofibers, as drug delivery systems for topical and transdermal applications. This approach employs increased drug concentration in the carrier, in order to increase drug flux into and through the skin. Both nanoparticles and nanofibers can be used to deliver hydrophobic and hydrophilic drugs and are capable of controlled release for a prolonged period of time. The examples presented provide significant evidence that this area of research has - and will continue to have - a profound impact on both clinical outcomes and the development of new products.

Clinical evaluation of an oil-based lubricant eyedrop in dry eye patients with lipid deficiency

PURPOSE

To evaluate and compare the efficacy of a lipid-based lubricant eyedrop formulation (hydroxypropyl guar/propylene glycol/phospholipid [HPG/PG/PL]) with preservative-free saline for the treatment of dry eye.

METHODS

This was a prospective, multicenter, randomized, single-masked, parallel-group phase 4 clinical study. Patients ≥18 years diagnosed with dry eye received 1 drop of saline 4 times daily (QID) for 15 days during a run-in phase, followed by randomization. Patients then instilled HPG/PG/PL or saline QID through day 35 and as needed through day 90. Change in tear film break-up time (TFBUT), change in total ocular surface staining (TOSS) score, and Impact of Dry Eye on Everyday Life (IDEEL) were evaluated on day 35.

RESULTS

Increase in TFBUT from baseline to day 35 was assessed during the interim and final analyses. Mean ± SE difference between the HPG/PG/PL (n = 110) and saline groups (n = 100) was 1.3 ± 0.4 seconds (interim analysis; 95% confidence interval [CI] 0.5-2.1 seconds; p = 0.0012) and 1.0 ± 0.3 seconds (final analysis; 95% CI 0.4-1.6 seconds; p = 0.0011), demonstrating the superiority of HPG/PG/PL. The mean ± SE difference between the HPG/PG/PL and saline groups for IDEEL treatment effectiveness scores was 16.0 ± 3.6 (95% CI 8.9-23.1; p<0.0001). No significant differences in TOSS scores or IDEEL inconvenience scores were observed between treatment groups.

CONCLUSIONS

Thirty-five days of QID HPG/PG/PL treatment resulted in a statistically significant improvement in TFBUT and IDEEL treatment effectiveness scores compared with saline but not in TOSS or IDEEL treatment inconvenience scores. HPG/PG/PL was well-tolerated by patients.

Mechanisms and management of dry eye in cataract surgery patients

PURPOSE OF REVIEW

To provide a summary of the mechanisms that may cause dry eye after cataract surgery and discuss available and upcoming treatment modalities.

RECENT FINDINGS

Development or worsening of dry eye symptoms after cataract surgery is multifactorial with corneal nerve transection, inflammation, goblet cell loss, and meibomian gland dysfunction commonly cited as underlying disorders. With increasing awareness of the prevalence of dry eye disease, current surgical techniques are being analyzed for their contribution to the issue. Although many classic interventions, such as artificial tears and anti-inflammatory drops, remain first-line treatment options, they may not adequately address abnormalities of the tear film. The trend has been to create new drugs and technologies that target meibomian gland deficiencies and restore goblet cell numbers.

SUMMARY

Therapy for postoperative dry eye symptoms should be determined based on symptom severity and which underlying cause is most prominent at a given time. Patients with high-level risk factors for dry eye should be evaluated preoperatively to determine whether they have preexisting dry eye disease or if they are susceptible to developing disease after surgery.

The pathophysiology, diagnosis, and treatment of dry eye disease

BACKGROUND

Dry eye disease (DED) is common; its prevalence around the world varies from 5% to 34%. Its putative pathogenetic mechanisms include hyperosmolarity of the tear film and inflammation of the ocular surface and lacrimal gland. Dry eye is clinically subdivided into two subtypes: one with decreased tear secretion (aqueous-deficient DED), and one with increased tear evaporation (hyperevaporative DED).

METHODS

This review is based on pertinent publications retrieved by a selective PubMed search and on the authors' own clinical and scientific experience.

RESULTS

The diagnostic evaluation of dry eye disease should include a detailed patient history, thorough split-lamp examination, and additional tests as indicated. Few randomized controlled therapeutic trials for dry eye have been published to date. Artificial tears of various kinds are recommended if the symptoms are mild. Lid hygiene is helpful in the treatment of hyperevaporative dry eye, while collagen or silicon plugs can be used for partial occlusion of the efferent lacrimal ducts to treat severe hyposecretory dry eye. The benefit of long-term topical anti-inflammatory treatment of moderate or severe dry eye disease with corticosteroids or cyclosporine A eye drops has been documented in clinical trials on a high evidence level. Orally administered tetraycycline derivatives and omega-3 or omega-6 fatty acids are also used.

CONCLUSION

The treatment of dry eye has evolved from tear substitution alone to a rationally based therapeutic algorithm. Current research focuses on pathophysiology, new diagnostic techniques, and novel therapies including secretagogues, topical androgens, and new anti- inflammatory drugs.

A Pragmatic Approach to the Management of Dry Eye Disease: Evidence into Practice

Dry eye disease (DED) is a highly prevalent chronic ocular disorder that can lead to significant discomfort and visual disturbance. It is a potentially debilitating condition that can have significant negative impact on quality of life. A diverse range of management options exists for DED, including tear supplement products, anti-inflammatory agents, immunomodulators, punctal occlusive devices, and environmental modifiers. Although the availability of a variety of treatment approaches provides clinical flexibility and can enable individualized care, it can also complicate clinical management decisions and lead to variability in the nature of the clinical care provided to patients. By considering two dry eye case scenarios, this review evaluates the currently available evidence relating to DED therapy to describe a pragmatic clinical approach to best-practice management of dry eye patients.

Advance of the application of nano-controlled release system in ophthalmic drug delivery

The ocular prescription application of nanometer materials are mainly concentrated in controlled release systems. Due to the unique properties of nanometer materials such as higher bioavailability and less side effects, it has great advantages in carrying ocular drugs of eye diseases compared with the traditional dosing method. As a result, nano-controlled release system has good application prospect in eye diseases. At present, a variety of different types of nano-controlled release systems have been used to enhance the efficiency of the ocular drugs including nanomicelles, nanoparticles, nanosuspensions, liposomes and dendrimers. In this article, the research progress and the application of nano-controlled release system in ophthalmic drug delivery are reviewed.