A Meta-Analysis of the Efficacy of Hyaluronic Acid Eye Drops for the Treatment of Dry Eye Syndrome

Different concentrations of hyaluronic acid eye drops for dry eye syndrome: a systematic review and Meta-analysis

AIM

To compare high or low concentration of hyaluronic acid eye drops (HY) for dry eye syndromes (DES).

METHODS

Randomized controlled trials (RCTs) comparing various concentrations of HY were searched in PubMed, Embase, Web of Science, Cochrane, SinoMed, CNKI, Wanfang Database, CQVIP, and Chinese journals databases between inception and July 2023. Pooled standardized mean differences (SMD) or weighted mean difference (WMD) with 95% confidence intervals (CI) from RCTs evaluating Schirmer's I test (SIT), corneal fluorescein staining score (CFS), tear breakup time (TBUT), DES score (DESS), and Ocular Surface Disease Index (OSDI) were calculated. Sensitivity analysis, Egger's test and Meta-regression analysis were performed for all indicators.

RESULTS

We conducted a Meta-analysis of 10 RCTs that met the inclusion criteria, involving 1796 cases. High-concentrations group significantly improved the outcome of CFS according to random effects modelling (SMD, -3.37; 95%CI, -5.25 to -1.48; P=0.0005). The rest of the results were not statistically significant, including indicators such as SIT, TBUT, DESS and OSDI.

CONCLUSION

For dry eyes with positive corneal staining, a high concentration of HY is recommended, whereas in other cases, a high concentration of HY does not offer a more pronounced advantage over a low concentration of HY in the treatment of dry eyes.

Efficacy of recombinant human epidermal growth factor plus sodium hyaluronate eye drops in diabetic dry eye post-cataract surgery

BACKGROUND

Dry eye syndrome (DES) after diabetic cataract surgery can seriously affect the patient's quality of life. Therefore, effective alleviation of symptoms in patients with this disease has important clinical significance.

AIM

To explore the clinical effect of recombinant human epidermal growth factor (rhEGF) plus sodium hyaluronate (SH) eye drops on DES after cataract surgery in patients with diabetes.

METHODS

We retrospectively evaluated 82 patients with diabetes who experienced DES after cataract surgery at Tianjin Beichen Hospital, Affiliated Hospital of Nankai University between April 2021 and April 2023. They were classified into an observation group (42 cases, rhEGF + SH eye drops) and a control group (40 cases, SH eye drops alone), depending on the different treatment schemes. The thera-peutic efficacy, dry eye symptom score, tear film breakup time (TFBUT), basic tear secretion score [assessed using Schirmer I test (SIt)], corneal fluorescein staining (FL) score, tear inflammatory markers, adverse reactions during treatment, and treatment satisfaction were compared between the two groups.

RESULTS

Therapeutic efficacy was higher in the observation group compared with the control group. Both groups showed improved TFBUT and dry eye, as well as improved SIt and FL scores after treatment, with a more pronounced improvement in the observation group. Although no marked differences in adverse reactions were observed between the two groups, treatment satisfaction was higher in the observation group.

CONCLUSION

rhEGF + SH eye drops rendered clinical benefits to patients by effectively ameliorating dry eye and visual impairment with favorable efficacy, fewer adverse reactions, and high safety levels. Thus, this treatment should be promoted in clinical practice.

Topical Insulin for Ocular Surface Disease

Background: Insulin and insulin-like growth factor (IGF)-1 receptors are present in ocular tissues such as corneal epithelium, keratocytes, and conjunctival cells. Insulin plays a crucial role in the growth, differentiation, and proliferation of corneal epithelial cells, as well as in wound healing processes in various tissues. Purpose: This review explores the potential role of topical insulin in the treatment of ocular surface diseases. Specifically, it examines its impact on corneal nerve regeneration, sub-basal plexus corneal nerves, and its application in conditions like corneal epithelial defects, dry eye disease, and diabetic keratopathy. Methods: The review analyzes studies conducted over the past decade that have investigated the use of topical insulin in ocular surface diseases. It focuses on indications, drug preparation methods, side effects, efficacy outcomes, and variations in insulin concentrations and dosages used. Results: While off-label use of topical insulin has shown promising results in refractory corneal epithelial defects, its efficacy in dry eye disease is yet to be demonstrated. Variations in concentrations, dilutions, and dosing guidelines have been reported. However, limited data on ocular penetration, ocular toxicity, and systemic side effects pose challenges to its widespread utility. Conclusion: This review synthesizes findings from ocular investigations on topical insulin to assess its potential applicability in treating ocular surface and corneal diseases. By highlighting indications, preparation methods, side effects, and efficacy outcomes, it aims to provide insights into the current status and future prospects of using topical insulin in ophthalmic practice.

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.

New advances in medical management of dry eye: optimizing treatment strategies for enhanced relief

PURPOSE

Dry eye disease (DED) is a prevalent ocular surface disease that is conventionally characterized by tear film hyperosmolarity and instability. This review presents a summarized classification of DED, followed by a comprehensive discussion of the most recent topical and systemic medications and clinical recommendations for selecting the most appropriate option for each patient.

METHODS

An extensive literature search was conducted on electronic databases, such as PubMed, Scopus, and Web of Science, using keywords including "dry eye syndrome," "ocular surface disease," "medical management," "artificial tears," "topical immunomodulators," and "meibomian gland dysfunction."

RESULTS

The underlying reasons for DED can range from insufficient aqueous tear production to increased tear evaporation. Recent literature has provided a more in-depth understanding of the pathophysiology of DED by examining the tear film's lipid, aqueous, and mucin layers. However, despite these advancements, medical management of patients with symptomatic DED has not fully reflected this modernized knowledge of its pathophysiology.

CONCLUSION

To develop a rationalized strategy for treating DED, it is crucial to have updated knowledge of therapeutic options, their mechanisms of actions, and indications based on the DED type and underlying causes.

Prostaglandin E2 may clinically alleviate dry eye disease by inducing Th17 cell differentiation

Dry eye (DE) is a multifactorial ocular surface disease characterised by an imbalance in tear homeostasis. The pathogenesis of DE is complex and related to environmental, immunological (e.g., T helper 17 cells) and other factors. However, the DE disease pathogenesis remains unclear, thereby affecting its clinical treatment. This study aimed to explore the mechanism through which prostaglandin E2 (PGE2) affects DE inflammation by regulating Th17. The DE mouse model was established through subcutaneous injection of scopolamine hydrobromide. The tear secretion test and break-up time (BUT) method were used to detect tear secretion and tear film BUT, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of PGE2, interleukin (IL)-17, IL-6 and tumour necrosis factor (TNF-α) in tear fluid and those of PGE2 and IL-17 in the serum. RT-qPCR and western blotting were used to test the mRNA and protein expression levels of IL-17 and retinoid-related orphan receptor-γt (RORγt). PGE2 was highly expressed in the DE mouse model. The mRNA and protein levels of IL-17 and the key Th17 transcription factor RORγt were increased in tissues of the DE mice. Moreover, PGE2 promoted tear secretion, reduced the BUT, increased the IL-17 concentration in tears and increased the Th17 cell proportion in DE, whereas the PGE2 receptor inhibitor AH6809 reversed the effects of PGE2 on tear secretion, BUT, and the Th17 cell proportion in draining lymph node (DLN) cells. Taken together, the study findings indicate that PGE2 could induce DE-related symptoms by promoting Th17 differentiation.

Topical diquafosol versus hyaluronic acid for the treatment of dry eye disease: a meta-analysis of randomized controlled trials

BACKGROUND

Diquafosol enhances fluid transfer and mucin secretion on ocular surface, which has been suggested as an effective treatment for dry eye disease (DED). The aim of the systematic review and meta-analysis was to compare the efficacy and safety of topical diquafosol versus hyaluronic acid (HA) for DED.

METHODS

Relevant randomized controlled trials were obtained via search of electronic including PubMed, Embase, Cochrane Library, and Web of Science. A random-effects model was used to pool the results after incorporating the influence of potential heterogeneity.

RESULTS

A total of nine RCTs involving 1295 patients with DED were included in the meta-analysis. Compared to treatment with 0.1% HA, topical treatment with 3% diquafosol significantly improved the Ocular Surface Disease Index (mean difference (MD): - 3.59, 95% confidence interval (CI): - 4.68 to - 2.50, p < 0.001; I2 = 6%), results of Schirmer's test (MD: 1.08 mm, 95% CI: 0.41 to 1.76, p = 0.002; I2 = 0%), tear breakup time (MD: 0.60 s, 95% CI: 0.20 to 0.99, p = 0.003; I2 = 63%), corneal fluorescein staining score (MD: - 0.20, 95% CI: - 0.37 to - 0.03, p = 0.02; I2 = 58%), and ocular rose bengal staining score (MD: - 0.62, 95% CI: - 0.88 to - 0.35, p < 0.001; I2 = 15%). No severe adverse events were reported. Topical use of diquafosol was associated with a higher risk of overall adverse events as compared to HA (odds ratio: 1.71, 95% CI: 1.08 to 2.71, p = 0.02; I2 = 18%).

CONCLUSIONS

Topical treatment with 3% diquafosol may be more effective than 0.1% HA for patients with DED. However, the long-term efficacy and tolerability of diquafosol still need to be determined.

Poloxamer sols endowed with in-situ gelability and mucoadhesion by adding hypromellose and hyaluronan for prolonging corneal retention and drug delivery

The purpose of this study was to develop poloxamer (P407)-based in-situ thermogellable hydrogels with reducing concentration of P407 by adding hypromellose (HPMC) and with enhancing mucoadhesion of resulting hydrogels by adding hyaluronic acid (HA) for prolonging ocular delivery of hydroxypropyl-β-cyclodextrin (HPβCD)-solubilized testosterone (TES). Results demonstrated that 0.5% TES solution was successfully solubilized with adding 10% HPβCD. Non-gellable 13% P407 sol became in-situ gellable with adding 2.0-2.5% HPMC and mucoadhesibility was further imporved with adding 0.3% HA-L (low MW) or HA-H (high MW). Optimized 0.5% HPβCD-solubilized TES P407-based thermogellable hydrogels with enhancement of mucoadhesion for prolonging ocular delivery comprised 13% P407, 2.5% HPMC, and 0.3% HA-L or HA-H. Furthermore, rheological measurements under simulated eye blinking confirmed that non-thixotropic properties of optimized hydrogels could be spreaded evenly and retain a greater amount of drug-loaded hydrogels on the ocular surface for a longer period to prolong drug delivery. Compared with conventional eye drops, the prolonged residence time of optimized hydrogels from ex vivo and in vivo studies were observed, indicating relationships between rheological properties and in vivo performances. It was concluded that P407-based thermosensitive hydrogels with reducing concentration of P407 and enhancing mucoadhesion was successfully formulated by adding 2.5% HPMC and 0.3% HA in 13% P407 for potentially accomplishing effective clinical treatment of DED.

The Effect of Sodium Hyaluronate Eye Drops 2, 4 or 6 Times a Day on Signs and Symptoms of Dry Eye Disease

Purpose

A randomized clinical trial was run to evaluate the effectiveness of a preservative-free 0.4% sodium hyaluronate eye drop (LOF) in different dosage schemes to alleviate signs and symptoms of dry eye disease (DED).

Methods

A total of 116 subjects with mild-to-moderate DED were included, and 111 completed the study (from which 67.6% were female and 65.3% were users of oral contraceptives). Patients were randomly assigned to instill a drop of LOF either 2 (BID), 4 (QID) or 6 (6TD) times a day (at least 3 hours apart) for 30 days. The clinical parameters and symptom endpoints were Ocular Surface Disease Index (OSDI), tear break-up time (TBUT), ocular surface staining, and conjunctival hyperemia. Other parameters evaluated were chemosis, best corrected visual acuity, and the incidence of adverse events (AE).

Results

There was a significant reduction in OSDI scores by day 30 in all groups. The recovery of the OSDI score back to normal values was observed in 51.4% of patients treated (50%, 48.6%, and 55.6% in BID, QID, and 6TD, respectively, p = 0.822). Similar improvement was observed for TBUT, 50.5% of patients increased this variable to >10 seconds (39.5%, 51.4%, and 61.1%, p = 0.175), and for ocular surface staining, ≥72% showed Grade 0. There were no significant differences among posology groups regarding ocular surface staining, conjunctival hyperemia, or any safety parameters. No overall improvement in OSDI and TBUT to normal values was noted for 31 patients (21 were female and 71.4% users of contraceptive drugs).

Conclusion

The ophthalmic use of preservative free LOF, 2, 4 or 6 times a day, may alleviate clinical parameters and symptoms in 50% of patients with mild-to-moderate DED after a one-month treatment. This improvement seemed to be less ubiquitous in patients within reproductive age and using oral contraceptives.

Trial Registration

This trial is registered at clinicaltrials.gov (NCT0704531).

A New Era in Ocular Therapeutics: Advanced Drug Delivery Systems for Uveitis and Neuro-Ophthalmologic Conditions

The eye's intricate anatomical barriers pose significant challenges to the penetration, residence time, and bioavailability of topically applied medications, particularly in managing uveitis and neuro-ophthalmologic conditions. Addressing this issue, polymeric nano-based drug delivery systems (DDS) have surfaced as a promising solution. These systems enhance drug bioavailability in hard-to-reach target tissues, extend residence time within ocular tissues, and utilize biodegradable and nanosized polymers to reduce undesirable side effects. Thus, they have stimulated substantial interest in crafting innovative treatments for uveitis and neuro-ophthalmologic diseases. This review provides a comprehensive exploration of polymeric nano-based DDS used for managing these conditions. We discuss the present therapeutic hurdles posed by these diseases and explore the potential role of various biopolymers in broadening our treatment repertoire. Our study incorporates a detailed literature review of preclinical and clinical studies from 2017 to 2023. Owing to advancements in polymer science, ocular DDS has made rapid strides, showing tremendous potential to revolutionize the treatment of patients with uveitis and neuro-ophthalmologic disorders.

Chloroquine and Hydroxychloroquine in the Treatment of Dry Eye Disease

The role of chloroquine (CQ) and hydroxychloroquine (HCQ) in the management of dry eye disease is still unclear. This systematic review and meta-analysis investigates the efficacy and feasibility of CQ and HCQ in patients with dry eye disease. In February 2023, PubMed, Embase, Google Scholar, and Web of Science were accessed. Data from 462 patients (mean age 54.4 ± 2.8 years) were collected. Compared to baseline, the tear breakup time (p < 0.0001) and Schirmer I test (p < 0.0001) were significantly increased, and the Ocular Surface Disease Index (OSDI, p < 0.0001) and corneal staining (p < 0.0001) were significantly decreased at the last follow-up in the CQ/HCQ group. At the last follow-up, the OSDI was significantly lower in the CQ/HCQ group compared to the control group (p < 0.0001). Corneal staining was significantly greater in the control group compared to the CQ/HCQ group (p < 0.0001). The Schirmer I test showed no significant difference between the groups (p = 0.2). Altogether, CQ and HCQ improved the symptoms and signs of dry eye disease.

Wearable and Invisible Sensor Design for Eye-Motion Monitoring Based on Ferrofluid and Electromagnetic Sensing Technologies

For many human body diseases, treatments in the early stages are more efficient and safer than those in the later stages; therefore, detecting the early symptoms of a disease is crucial. One of the most significant early indicators for diseases is bio-mechanical motion. This paper provides a unique way of monitoring bio-mechanical eye motion based on electromagnetic sensing technology and a ferro-magnetic material, ferrofluid. The proposed monitoring method has the advantages of being inexpensive, non-invasive, sensor-invisible and extremely effective. Most of the medical devices are cumbersome and bulky, which makes them hard to apply for daily monitoring. However, the proposed eye-motion monitoring method is designed based on ferrofluid eye make-up and invisible sensors embedded inside the frame of glasses such that the system is wearable for daily monitoring. In addition, it has no influence on the appearance of the patient, which is beneficial for the mental health of some patients who do not want to attract public attention during treatment. The sensor responses are modelled using finite element simulation models, and wearable sensor systems are created. The designed frame of the glasses is manufactured based on 3-D printing technology. Experiments are conducted to monitor eye bio-mechanical motions, such as the frequency of eye blinking. Both the quick blinking behaviour with an overall frequency of around 1.1 Hz and the slow blinking behaviour with an overall frequency of around 0.4 Hz can be observed through experimentation. Simulations and measurements results show that the proposed sensor design can be employed for bio-mechanical eye-motion monitoring. In addition, the proposed system has the advantages of invisible sensor set-up and will not affect the appearance of the patient, which is not only convenient for the daily life of the patient but also beneficial for mental health.

Effectiveness of Topical Cyclosporin-A 0.1% Compared to Combined Topical Cyclosporin-A 0.1% with Topical Sodium Hyaluronate on Interleukin-6 Levels in the Tears of Patients with Dry Eye Disease

Introduction: Pro-inflammatory cytokines are important contributors to dry eye disease (DED). The cytokine interleukin (IL)-6 has become a therapeutic target in several DED drug studies. This randomized controlled trial aimed to determine the effectiveness of topical cyclosporin-A 0.1% compared to the combination of topical cyclosporin-A 0.1% and sodium hyaluronate in reducing tear IL-6 levels in DED patients. Methods: The participants were 20 patients, each with two eyes, who had moderate-to-severe DED. Before and after treatment, the clinical degree of DED was examined in each group, using ocular surface disease index (OSDI) scores, tear break-up time (TBUT), fluorescent tests, and Schirmer I tests. In addition, tear samples were taken to examine IL-6 levels through the ELISA method. The results were analyzed using the t-test, Wilcoxon test, and Mann–Whitney test. The correlation between tear IL-6 levels and the severity of DED was analyzed using the Spearman correlation test. Results: The study showed a significantly lower tear IL-6 level, OSDI score, and degree of ocular staining after either topical cyclosporin-A 0.1% or a combination of topical cyclosporin-A 0.1% and sodium hyaluronate (all values p < 0.05). Conclusions: The combination therapy was superior in reducing tear IL-6 levels. In addition, a correlation existed between tear IL-6 levels and the severity of DED based on the TBUT, although it was weak and not statistically significant.

Hyaluronic acid - PVA films for the simultaneous delivery of dexamethasone and levofloxacin to ocular tissues

Ocular drug delivery is challenging due to the poor drug penetration across ocular barriers and short retention time of the formulation at the application site. Films, applied as inserts or implants, can be used to increase residence time while controlling drug release. In this work, hydrophilic films made of hyaluronic acid and two kinds of PVA were loaded with dexamethasone (included as hydroxypropylcyclodextrin complex) and levofloxacin. This association represents one of the main treatments for the post cataract surgery management, and it is also promising for eye infections whith pain and inflammation. Films were characterized in terms of swelling and drug release and were then applied to porcine eye bulbs and isolated ocular tissues. Film swelling leads to the formation of either a gel (3D swelling) or a larger film (2D swelling) depending on the type of PVA used. Films, prepared in an easy and scalable method, demonstrated high loading capacity, controlled drug release and the capability to deliver dexamethasone and levofloxacin to the cornea and across the sclera, to potentially target also the posterior eye segment. Overall, this device can be considered a multipurpose delivery platform intended for the concomitant release of lipophilic and hydrophilic drugs.

Eye drops of human origin-Current status and future needs: Report on the workshop organized by the ISBT Working Party for Cellular Therapies

BACKGROUND AND OBJECTIVES

Serum eye drops (SEDs) are used to treat ocular surface disease (OSD) and to promote ocular surface renewal. However, their use and production are not standardized, and several new forms of human eye drops have been developed.

MATERIALS AND METHODS

The International Society for Blood Transfusion Working Party (ISBT WP) for Cellular Therapies held a workshop to review the current types of eye drops of human origin (EDHO) status and provide guidance.

RESULTS

The ISBT WP for Cellular Therapies introduced the new terminology 'EDHO' to emphasize that these products are analogous to 'medical products of human origin'. This concept encompasses their source (serum, platelet lysate, and cord blood) and the increasingly diverse spectrum of clinical usage in ophthalmology and the need for traceability. The workshop identified the wide variability in EDHO manufacturing, lack of harmonized quality and production standards, distribution issues, reimbursement schemes and regulations. EDHO use and efficacy is established for the treatment of OSD, especially for those refractory to conventional treatments.

CONCLUSION

Production and distribution of single-donor donations are cumbersome and complex. The workshop participants agreed that allogeneic EDHO have advantages over autologous EDHO although more data on clinical efficacy and safety are needed. Allogeneic EDHOs enable more efficient production and, when pooled, can provide enhanced standardization for clinical consistency, provided optimal margin of virus safety is ensured. Newer products, including platelet-lysate- and cord-blood-derived EDHO, show promise and benefits over SED, but their safety and efficacy are yet to be fully established. This workshop highlighted the need for harmonization of EDHO standards and guidelines.

Eye Care Behaviors among Adults in Poland: A Nationwide Cross-Sectional Survey

Implementation of eye care behaviors may reduce the risk of eye symptoms and diseases. This study aimed to assess eye care behaviors and identify factors associated with eye care practices among adults in Poland. This cross-sectional survey was carried out between 9 and 12 December 2022 on a nationwide random quota sample of adults in Poland. The study questionnaire included a set of questions on 10 different eye care behaviors. The study population included 1076 participants with a mean age of 45.7 ± 16.2 years, and 54.2% of participants were females. The most common (30.2%) eye care behavior was the use of good lighting indoors, and 27.3% used sunglasses with a UV filter. More than one-fifth of participants declared taking regular screen breaks and limiting screen time. Less than one-tenth of participants used dietary supplements with lutein, beta-carotene, or zinc. Out of 12 factors assessed in this study, self-reported knowledge of eye diseases was the most important factor associated (p < 0.05) with eye care behaviors. There were no economic or educational gaps (p > 0.05) in the implementation of most of the eye care behaviors among adults in Poland. This study revealed a low level of implementation of eye care behaviors among adults in Poland.

A Critical Appraisal of the Physicochemical Properties and Biological Effects of Artificial Tear Ingredients and Formulations

Dry eye disease is among the most prevalent diseases affecting the ocular surface. Artificial tears remain the cornerstone therapy for its management. There are currently a wide variety of marketed artificial tears available to choose from. These artificial tears differ significantly in their composition and formulation. This article reviews the physicochemical and biological properties of artificial tear components and how these characteristics determine their use and efficacy in the management of dry eye. Furthermore, this article also discusses the various formulations of artificial tears such as macro and nanoemulsion and the type of preservatives present in them.

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.

Hyaluronic acid in the treatment of dry eye disease

Dry eye disease (DED) is a highly prevalent and debilitating condition affecting several hundred million people worldwide. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan commonly used in the treatment of DED. This review aims to critically evaluate the literature on the safety and efficacy of artificial tears containing HA used in DED treatment. Literature searches were conducted in PubMed, including MEDLINE, and in Embase via Ovid with the search term: "(hyaluronic acid OR hyaluronan OR hyaluronate) AND (dry eye OR sicca)". A total of 53 clinical trials are included in this review, including eight placebo-controlled trials. Hyaluronic acid concentrations ranged from 0.1% to 0.4%. Studies lasted up to 3 months. A broad spectrum of DED types and severities was represented in the reviewed literature. No major complications or adverse events were reported. Artificial tears containing 0.1% to 0.4% HA were effective at improving both signs and symptoms of DED. Two major gaps in the literature have been identified: 1. no study investigated the ideal drop frequency for HA-containing eyedrops, and 2. insufficient evidence was presented to recommend any specific HA formulation over another. Future investigations assessing the optimal drop frequency for different concentrations and molecular weights of HA, different drop formulations, including tonicity, and accounting for DED severity and aetiology are essential for an evidence-based, individualized approach to DED treatment.

Hyaluronic acid in the treatment of dry eye disease

Dry eye disease (DED) is a highly prevalent and debilitating condition affecting several hundred million people worldwide. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan commonly used in the treatment of DED. This review aims to critically evaluate the literature on the safety and efficacy of artificial tears containing HA used in DED treatment. Literature searches were conducted in PubMed, including MEDLINE, and in Embase via Ovid with the search term: "(hyaluronic acid OR hyaluronan OR hyaluronate) AND (dry eye OR sicca)". A total of 53 clinical trials are included in this review, including eight placebo-controlled trials. Hyaluronic acid concentrations ranged from 0.1% to 0.4%. Studies lasted up to 3 months. A broad spectrum of DED types and severities was represented in the reviewed literature. No major complications or adverse events were reported. Artificial tears containing 0.1% to 0.4% HA were effective at improving both signs and symptoms of DED. Two major gaps in the literature have been identified: 1. no study investigated the ideal drop frequency for HA-containing eyedrops, and 2. insufficient evidence was presented to recommend any specific HA formulation over another. Future investigations assessing the optimal drop frequency for different concentrations and molecular weights of HA, different drop formulations, including tonicity, and accounting for DED severity and aetiology are essential for an evidence-based, individualized approach to DED treatment.

Therapeutic Hyper-CL soft contact lens in Sjögren's syndrome

Purpose

Observations

Conclusions and importance

Acupuncture for the management of dry eye disease

The effectiveness of using acupuncture for dry eye disease (DED) is controversial. Thus, this systematic review investigated the effectiveness and feasibility of using acupuncture for DED in accordance with the 2020 PRISMA statement. The outcomes of interests were (1) to evaluate the efficacy of acupuncture in improving the ocular surface disease index (OSDI), Schirmer I test score, and tear breakup time from baseline to the last follow-up; (2) to determine possible complications of using acupuncture; and (3) to investigate the superiority of acupuncture over other commonly used treatments for DED. Data from 394 patients were collected. Results showed that acupuncture significantly prolonged the tear breakup time (P < 0.0001), significantly increased the Schirmer I test score (P < 0.0001), and significantly reduced the OSDI (P < 0.0001) from baseline to the last follow-up. Compared with the control group, the acupuncture group had significantly greater Schirmer I test score (P < 0.0001), significantly longer tear breakup time (P = 0.0004), and significantly lower OSDI (P = 0.002). These results suggest that acupuncture is effective and feasible in improving symptoms and signs of DED. No severe adverse effects of acupuncture were observed.

Clinical Efficacy, Tolerability and Safety of a New Multiple-Action Eyedrop in Subjects with Moderate to Severe Dry Eye

Background: To assess the clinical efficacy, tolerability and safety of a new-generation ophthalmic solution containing cross-linked hyaluronic acid 0.15% trehalose 3%, liposomes 1% and sterylamine 0.25% (Trimix® Off Health Italia, Firenze, Italy) (CXHAL) versus trehalose 3% (Thealoz®, Thea Pharmaceuticals, Clermont-Ferrand, France) (TRS) in subjects with moderate to severe dry eye disease (DED). Patients and methods: In this prospective, observational cohort study, 41 subjects with moderate to severe dry eye were enrolled and divided into two age- and sex-matched groups. Group 1 was treated with CXHA eye drops, and group 2 was treated with TRS eye drops four times daily for 2 months. All subjects were evaluated at baseline (V0) and at day 60 ± 3 (V1). The examination comprised Best Corrected Visual Acuity (BCVA) and Symptom Assessment in Dry Eye (SANDE). Tear osmolarity was evaluated using the TearLab Osmolarity System®; Keratograph 5M (Oculus, Wetzlar, Germany) was performed to assess tear meniscus height (TMH), fluorescein tear break-up time (TBUT) and corneal and conjunctival fluorescein staining and meibography; furthermore, slit lamp evaluation was performed for eyelid erythema and edema, conjunctival chemosis and hyperemia and Meibomian gland secretion quality. Results: All patients completed the treatment. BCVA remained stable in both groups, and no adverse events were reported. After 2 months, both groups showed statistically significant improvements for SANDE (p = 0.001 and p = 0.012, respectively), TBUT values (p < 0.001 and p < 0.001, respectively) and staining (p = 0.004 and p = 0.001, respectively) as compared to baseline values. Group 1 showed a statistically significant improvement in SANDE frequency and tear osmolarity (p = 0.02 and p = 0.001, respectively), whereas chemosis was significantly reduced in group 2. The amount of TBUT improvement was statistically higher in group 1 compared to that in group 2 (p = 0.041). Conclusion: A new-generation multiple-action ophthalmic solution was safe and clinically effective in the treatment of moderate and severe dry eye, with significant improvements in the main ocular surface parameters.

Efficacy of Topical Administration of Corticosteroids for the Management of Dry Eye Disease: Systematic Review and Meta-Analysis

The efficacy of corticosteroids (CS) for dry eye disease (DED) has been investigated in the clinical setting. The present study investigated whether topical CS application improves the clinical outcome at last follow-up compared to the baseline. The present study was conducted according to the PRISMA 2020. All the randomized clinical trials (RCTs), which investigated the efficacy of corticosteroids in the management of DED, were accessed. In September 2022, the following databases were accessed: Pubmed, Web of Science, Google Scholar, and Embase. The following data were extracted at baseline and at last follow-up: Ocular Surface Disease Index (OSDI), tear breakup time test (TBUT), Schirmer I test (SIT), and corneal staining. Data from 425 patients were retrieved. A total of 69.4% (295 of 425 patients) were women. CS were effective to improve SIT (p = 0.02) and corneal staining (p = 0.003) at the last follow-up of 10.0 ± 15.3 weeks. TBUT was greater in the CS than in the control group at the last follow-up (p = 0.002). Concluding, topical CS administration led to an increase of SIT and a reduction of corneal staining at a mean of 10 weeks follow-up in patients with DED. Compared to a control group, topical CS administration evidenced greater values of TBUT. Altogether, a good safety profile was witnessed in DED patients receiving CS. However, different safety profiles of different CS formulations were not investigated due to a lack of quantitative data. The exact dosing frequency, duration of therapy, and favorable potency of the CS are still under investigation. Future randomized, controlled trials with larger sample sizes are warranted to provide higher-quality evidence to establish the role of CS in DED.

Prospective bacterial and fungal sources of hyaluronic acid: A review

The unique biological and rheological properties make hyaluronic acid a sought-after material for medicine and cosmetology. Due to very high purity requirements for hyaluronic acid in medical applications, the profitability of streptococcal fermentation is reduced. Production of hyaluronic acid by recombinant systems is considered a promising alternative. Variations in combinations of expressed genes and fermentation conditions alter the yield and molecular weight of produced hyaluronic acid. This review is devoted to the current state of hyaluronic acid production by recombinant bacterial and fungal organisms.

Cysteamine Eye Drops in Hyaluronic Acid Packaged in Innovative Single-Dose Systems: Stability and Ocular Biopermanence

Cystinosis is a rare genetic disorder characterized by the accumulation of cystine crystals in different tissues and organs causing, among other symptoms, severe ocular manifestations. Cysteamine eye drops are prepared in hospital pharmacy departments to facilitate access to treatment, for which vehicles that provide adequate biopermanence, as well as adaptable containers that maintain its stability, are required. Difficulties related to cysteamine preparation, as well as its tendency to oxidize to cystamine, show the importance of conducting rigorous galenic characterization studies. This work aims to develop and characterize an ophthalmic compounded formulation of cysteamine prepared with hyaluronic acid and packaged in innovative single-dose systems. For this task, the effect of different storage temperatures and the presence/absence of nitrogen on the physicochemical stability of the formulation and its packaging was studied in a scaled manner, until reaching the optimal storage conditions. The results showed that 0.55% cysteamine, prepared with hyaluronic acid and packaged in single-dose containers, is stable for 30 days when stored at −20 °C. In addition, opening vials every 4 h at room temperature after 30 days of freezing maintains the stability of the cysteamine formulation for up to 16 h. Moreover, ocular biopermanence studies were conducted using molecular imaging, concluding that the biopermanence offered by the vehicle is not affected by the freezing process, where a half-life of 31.11 min for a hyaluronic acid formulation stored for 30 days at −20 °C was obtained, compared with 14.63 min for 0.9% sodium chloride eye drops.

Functionalized Hyaluronic Acid for “In Situ” Matrix Metalloproteinase Inhibition: A Bioactive Material to Treat the Dry Eye Sydrome

Hyaluronic acid (HA) is a naturally occurring polysaccharide with many molecular functions, including maintaining the structure and physiology of the tissues, tissue remodeling, and inflammation. HA is found naturally in physiological tear fluid, possesses excellent mucus-layer-adhesive properties, and is successfully employed in the treatment of dry eye syndrome (DES). However, HA has as major drawback: its rapid in vivo degradation by hyaluronidase. We report on a unique material, namely, HA-3, obtained by the functionalization of HA with the metalloproteinase inhibitor 3 (MMPI). This material is characterized by an increased resistance to hyaluronidase degradation, associated with MMP inhibition properties. The ability of HA-3 to prevent dehydration of human corneal epithelial cells in vitro and in vivo may accelerate the development of more efficient DES treatment and broaden the application of HA in human diseases.

Supportive treatment to chemotherapy with MMC, in patients with ocular surface squamous neoplasia or conjunctival melanocytic tumor

PURPOSE

Since there is a lack of clear information regarding the benefit to combine supportive therapies (such as artificial tears) to mitomycin C (MMC) in the treatment of ocular surface neoplasia, the primary purpose of the study was to evaluate hyaluronic acid eye drops and hyaluronic acid-conjugated lactobionic acid (LACTOyal FREE) eye drops as supportive therapy.

METHODS

Retrospective evaluation of patients with ocular surface squamous neoplasia or conjunctival melanocytic tumor treated with MMC, who had used also artificial tears as supportive treatment. A 6-month follow-up with evaluation of subjective and objective tests for ocular surface integrity was conducted.

RESULTS

A total of 35 patients were analyzed, most of them with squamous disease (71.4%). The break-up time (BUT), Ocular Surface Disease Index (OSDI) and Schirmer test values showed a significant difference at any time point with overall population. No statistical difference was found among subgroups (Lactoyal vs No Lactoyal).

CONCLUSION

The use of an ancillary therapy based on hyaluronic acid allows to improve both subjective and objective ocular parameters, reducing MMC induced adverse effects. Meantime, hyaluronic acid-conjugated lactobionic acid eye drops highlighted the same advantages with a more positive trend in OSDI results.

Short-term Efficacy and Safety of Biological Tear Substitutes and Topical Secretagogues for Dry Eye Disease: A Systematic Review and Network Meta-analysis

PURPOSE

The purpose of this study was to assess short-term efficacy and safety of tear promotion eye drops (biological tear substitutes and topical secretagogues) for treating dry eye disease.

METHODS

Randomized controlled trials comparing short-term effects of biological tear substitutes or topical secretagogues versus placebo or other topical dry eye treatments in adults with dry eye disease were identified from the MEDLINE, Embase, Scopus, ClinicalTrials.gov , and World Health Organization International Clinical Trials Registry Platform databases. Pairwise meta-analysis and network meta-analysis were performed. Outcomes were ocular symptoms, ocular surface staining, tear break-up time, Schirmer test, and adverse events. The certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Thirty-nine randomized controlled trials (3693 patients) were eligible. Using artificial tears as a reference, autologous platelet lysate was the most effective treatment for lowering ocular surface disease index (unstandardized mean difference [USMD] -31.85; 95% confidence interval [CI]: -43.19 to -20.51) and platelet rich plasma showed the most reduction in corneal fluorescein staining scores (standardized mean difference -2.52; 95% CI: -3.23 to -1.82). Cord blood serum was the most effective treatment for increasing tear break-up time (USMD 2.67; 95% CI: 0.53-4.82), and eledoisin was superior to others in improving Schirmer scores (USMD 2.28; 95% CI: 0.14-4.42). Most interventions did not significantly increase ocular adverse events compared with artificial tears.

CONCLUSIONS

Biological tear substitutes, including autologous serum, autologous platelet lysate, platelet rich plasma, and cord blood serum, might be the most effective treatment among tear promotion eye drops in relieving dry eye symptoms without increasing adverse events. However, there remains uncertainty around these findings because of low/very low certainty of evidence.

Shear-Thinning and Temperature-Dependent Viscosity Relationships of Contemporary Ocular Lubricants

PURPOSE

To evaluate the shear viscosity of contemporary, commercially available ocular lubricants at various shear rates and temperatures and to derive relevant mathematical viscosity models that are impactful for prescribing and developing eye drops to treat dry eye disease.

METHODS

The shear viscosity of 12 ocular lubricants was measured using a rheometer and a temperature-controlled bath at clinically relevant temperatures at which users may experience exposure to the drops (out of the refrigerator [4.3°C]; room temperature [24.6°C]; ocular surface temperature [34.5°C]). Three replicates for each sample at each temperature were obtained using a standard volume (0.5 mL) of each sample. The viscosity of each ocular lubricant was measured over the full range of shear rates allowed by the rheometer.

RESULTS

The shear viscosity of the same ocular lubricant varied significantly among the three temperatures. In general, a higher temperature resulted in smaller viscosities than a lower temperature (an average of -48% relative change from 4.3°C to 24.6°C and -21% from 24.6°C to 34.5°C). At a constant temperature, the viscosity of an ocular lubricant over the studied shear rates can be well approximated by a power-law model.

CONCLUSIONS

Rheological analysis revealed that the ocular lubricants exhibited shear-thinning behavior at the measured temperatures. Differences in the ocular lubricants' formulations and measured temperatures resulted in different viscosities.

TRANSLATIONAL RELEVANCE

When prescribing eye drops, eye care professionals can select the optimal one for their patients by considering a variety of factors, including its rheological property at physiologically relevant shear rates and temperatures, which can improve residence time on the ocular surface, while ensuring appropriate comfort and vision. However, care must be taken when using the derived mathematical models in this study because the in vivo shear behavior of the ocular lubricants has not been examined and might show deviations from those reported when placed on the ocular surface.

Evaluation of the Lubricating Effect of Hyaluronic Acid on Contact Lenses Using a Pendulum-Type Friction Tester Under Mimicking Physiological Conditions

OBJECTIVE

To evaluate the lubricating effect of hyaluronic acid (HA) on soft contact lenses (SCLs) measured using a pendulum-type friction tester.

METHODS

We measured the coefficient of friction (CoF) of narafilcon A, delefilcon A, and etafilcon A with polyvinylpyrrolidone (PVP), daily disposable SCL material, using a modified pendulum-type friction tester. Sample SCLs were set on an acrylic plastic half-ball and placed into the polyethylene terephthalate hemisphere cup filled with 0.4 mL of test lubricants that included saline and 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% (wt/vol) HA (molecular weight, 850 kDa). The viscosities of saline and HA were measured using an Ubbelohde viscometer.

RESULTS

The CoF of the SCL under a low concentration (0.05%) of HA was the lowest and significantly lower than saline in narafilcon A and delefilcon A (P<0.05, Steel multiple comparison test). Under higher HA concentrations (0.3%, 0.4%, and 0.5%), the CoF was significantly higher than that of saline (P<0.01, Steel' multiple comparison test) in all three SCLs. There were no significant differences of CoF among three SCLs in saline and all concentrations of HA. The HA viscosities increased exponentially with the concentration (Y=1.2829e9.286X).

CONCLUSION

The viscosity of a high concentration of HA may increase the friction of SCLs, which may have a deleterious effect on the ocular surface.

Clinical efficacy of diquafosol sodium 3% versus hyaluronic acid 0.1% in patients with dry eye disease after cataract surgery: a protocol for a single-centre, randomised controlled trial

INTRODUCTION

The number of cataract surgeries, the most common ophthalmic surgery, is expected to increase due to ageing populations. Dry eye disease (DED) is a frequent side effect of cataract surgery, contributing to lower postoperative patient satisfaction and suboptimal quality of vision. It is unclear which eye-drops commonly used in these patients should be recommended for postoperative DED treatment. This study aims to compare the efficacy of topical administration of diquafosol sodium 3% vs hyaluronic acid 0.1% eye-drops in patients with DED after cataract surgery.

METHODS AND ANALYSIS

The study is designed as a single-blind randomised controlled trial. The participants will be randomly (1:1) allocated to either the diquafosol sodium 3% topical administration group (n=21) or the hyaluronic acid 0.1% topical administration group (n=21). Each group will receive its assigned eye-drop intervention over a 12-week period. The primary outcome will be measured using the total score of the Japanese version of the Ocular Surface Disease Index during the visit 5 weeks postoperatively. Both groups will be followed up after their respective eye-drop application for 12 weeks according to the intervention regimens. Secondary outcome measures including meibomian gland function assessment, tear film break-up time, keratoconjunctival staining score, maximum blink interval and tear secretion volume using Schirmer's test I will be assessed at 1, 5, 9, 13 and 25 weeks postoperatively.

ETHICS AND DISSEMINATION

This study has been approved by the Juntendo Hospital Certified Review Board, Tokyo, Japan (Approved protocol V.7.0 dated 7 May 2021. Approval number: J20-018) and has been registered with the Japan Registry of Clinical Trials. Written informed consent will be collected from every patient prior to study participation. The results of this trial will be presented at local and international meetings and submitted to peer-reviewed journals for publication.

TRIAL REGISTRATION NUMBER

jRCT1031210018.

Potential Ophthalmological Application of Extracts Obtained from Tuna Vitreous Humor Using Lactic Acid-Based Deep Eutectic Systems

A green technique was developed to extract hyaluronic acid (HA) from tuna vitreous humor (TVH) for its potential application in managing dry eye disease. Deep eutectic solvents (DES) were used to extract HA and were synthesized using natural compounds (lactic acid, fructose, and urea). The DES, the soluble fraction of TVH in DES (SF), and the precipitated extracts (PE) were evaluated for their potential use in dry eye disease treatment. In vitro experiments on human corneal epithelial cell lines and the effect on dry eye-associated microorganisms were performed. The influence of the samples on the HCE viability, their intracellular reactive oxygen species (ROS) scavenging capacity, inflammatory response, and antimicrobial properties were studied. According to the results, all samples displayed an antioxidant effect, which was significantly higher for PE in comparison to SF. Most of the tested samples did not induce an inflammatory response in cells, which confirmed the safety in ophthalmic formulations. In addition, the DES and SF proved to be efficient against the studied bacterial strains, while PE did not show an antimicrobial effect. Hence, both DES and SF at defined concentrations could be used as potential compounds in dry eye disease management.

Corneal protective effects of novel tear substitutes containing sodium hyaluronate and dodecahydrosqualene, squalane, in a porcine dry eye model

To develop a novel tear substitute (TS) containing sodium hyaluronate (SH) and dodecahydrosqualene (DHS, squalane), we improved the prescription of a previously developed TS containing saline, 0.5% SH and 1% castor oil (CO), which had corneal protective effects against 60-min desiccation in a porcine dry eye model and viscosity of 106.8 mPa·S. Fresh porcine eyes were treated with a TS containing saline, 0.1%, 0.25%, 0.3% or 0.5% SH, and 1% CO or 1%, 2.5% or 5% DHS, and TS-treated eyes were desiccated for up to 180 min. The corneal damage was evaluated by the staining score of methylene blue (MB), absorbance of MB extracted from the cornea, the staining density of lissamine green (LG) and histopathology. The viscosities of the examined TS were also measured. A saline/0.5% SH/1% DHS solution had corneal protective effects for 90 min under desiccation and a viscosity of 110.0 mPa·s. A TS with saline, 0.1%, 0.25% or 0.3% SH and 1% or 2.5% DHS did not have better protective effects than a saline/0.5% SH/1% DHS solution, although a saline/0.3% SH/5% DHS solution exhibited greater corneal protection against 180-min desiccation on MB and LG staining and histopathological examination, and its viscosity was 34.5 mPa·s, which was similar to the 29.5 mPa·s of 0.3% SH. The saline/0.3% SH/5% DHS solution is available as a novel 3-hr long-lasting TS containing mucinomimetic and liquid oil components to treat and relieve dry eye symptoms in animals and humans.

Effects of Topical Gabapentin on Ocular Pain and Tear Secretion

Neuropathic ocular pain is a frequent occurrence in medium to severe dry eye disease (DED). Only palliative treatments, such as lubricants and anti-inflammatory drugs, are available to alleviate patients’ discomfort. Anesthetic drugs are not indicated, because they may interfere with the neural feedback between the cornea and the lacrimal gland, impairing tear production and lacrimation. Gabapentin (GBT) is a structural analog of gamma-amino butyric acid that has been used by systemic administration to provide pain relief in glaucomatous patients. We have already shown in a rabbit model system that its topic administration as eye drops has anti-inflammatory properties. We now present data on rabbits’ eyes showing that indeed GBT given topically as eye drops has analgesic but not anesthetic effects. Therefore, opposite to an anesthetic drug such as oxybuprocaine, GBT does not decrease lacrimation, but–unexpectedly–even stimulates it, apparently through the upregulation of acetylcholine and norepinephrine, and by induction of aquaporin 5 (AQP5) expression in the lacrimal gland. Moreover, data obtained in vitro on a primary human corneal epithelial cell line also show direct induction of AQP5 by GBT. This suggests that corneal cells might also contribute to the lacrimal stimulation promoted by GBT and participate with lacrimal glands in the restoration of the tear film, thus reducing friction on the ocular surface, which is a known trigger of ocular pain. In conclusion, GBT is endowed with analgesic, anti-inflammatory and secretagogue properties, all useful to treat neuropathic pain of the ocular surface, especially in case of DED.